diff --git a/src/libslic3r/GCode.cpp b/src/libslic3r/GCode.cpp
index d5ee6a0484..81880831f1 100644
--- a/src/libslic3r/GCode.cpp
+++ b/src/libslic3r/GCode.cpp
@@ -169,6 +169,9 @@ static inline Point wipe_tower_point_to_object_point(GCode &gcodegen, const Vec2
 
 std::string WipeTowerIntegration::append_tcr(GCode &gcodegen, const WipeTower::ToolChangeResult &tcr, int new_extruder_id) const
 {
+    if (new_extruder_id != -1 && new_extruder_id != tcr.new_tool)
+        throw std::invalid_argument("Error: WipeTowerIntegration::append_tcr was asked to do a toolchange it didn't expect.");
+
     std::string gcode;
 
     // Toolchangeresult.gcode assumes the wipe tower corner is at the origin
@@ -182,8 +185,11 @@ std::string WipeTowerIntegration::append_tcr(GCode &gcodegen, const WipeTower::T
         end_pos = Eigen::Rotation2Df(alpha) * end_pos;
         end_pos += m_wipe_tower_pos;
     }
-    std::string tcr_rotated_gcode = tcr.priming ? tcr.gcode : rotate_wipe_tower_moves(tcr.gcode, tcr.start_pos, m_wipe_tower_pos, alpha);
-    
+
+    Vec2f wipe_tower_offset = tcr.priming ? Vec2f::Zero() : m_wipe_tower_pos;
+    float wipe_tower_rotation = tcr.priming ? 0.f : alpha;
+
+    std::string tcr_rotated_gcode = post_process_wipe_tower_moves(tcr, wipe_tower_offset, wipe_tower_rotation);
 
     // Disable linear advance for the wipe tower operations.
     gcode += (gcodegen.config().gcode_flavor == gcfRepRap ? std::string("M572 D0 S0\n") : std::string("M900 K0\n"));
@@ -285,17 +291,21 @@ std::string WipeTowerIntegration::append_tcr(GCode &gcodegen, const WipeTower::T
 
 // This function postprocesses gcode_original, rotates and moves all G1 extrusions and returns resulting gcode
 // Starting position has to be supplied explicitely (otherwise it would fail in case first G1 command only contained one coordinate)
-std::string WipeTowerIntegration::rotate_wipe_tower_moves(const std::string& gcode_original, const Vec2f& start_pos, const Vec2f& translation, float angle) const
+std::string WipeTowerIntegration::post_process_wipe_tower_moves(const WipeTower::ToolChangeResult& tcr, const Vec2f& translation, float angle) const
 {
-    std::istringstream gcode_str(gcode_original);
+    Vec2f extruder_offset = m_extruder_offsets[tcr.initial_tool].cast<float>();
+
+    std::istringstream gcode_str(tcr.gcode);
     std::string gcode_out;
     std::string line;
-    Vec2f pos = start_pos;
-    Vec2f transformed_pos;
+    Vec2f pos = tcr.start_pos;
+    Vec2f transformed_pos = pos;
     Vec2f old_pos(-1000.1f, -1000.1f);
 
     while (gcode_str) {
         std::getline(gcode_str, line);  // we read the gcode line by line
+
+        // All G1 commands should be translated and rotated
         if (line.find("G1 ") == 0) {
             std::ostringstream line_out;
             std::istringstream line_str(line);
@@ -317,17 +327,34 @@ std::string WipeTowerIntegration::rotate_wipe_tower_moves(const std::string& gco
 
             if (transformed_pos != old_pos) {
                 line = line_out.str();
-                char buf[2048] = "G1";
+                std::ostringstream oss;
+                oss << std::fixed << std::setprecision(3) << "G1 ";
                 if (transformed_pos.x() != old_pos.x())
-                    sprintf(buf + strlen(buf), " X%.3f", transformed_pos.x());
+                    oss << " X" << transformed_pos.x() - extruder_offset.x();
                 if (transformed_pos.y() != old_pos.y())
-                    sprintf(buf + strlen(buf), " Y%.3f", transformed_pos.y());
+                    oss << " Y" << transformed_pos.y() - extruder_offset.y();
 
-                line.replace(line.find("G1 "), 3, buf);
+                line.replace(line.find("G1 "), 3, oss.str());
                 old_pos = transformed_pos;
             }
         }
+
         gcode_out += line + "\n";
+
+        // If this was a toolchange command, we should change current extruder offset
+        if (line == "[toolchange_gcode]") {
+            extruder_offset = m_extruder_offsets[tcr.new_tool].cast<float>();
+
+            // If the extruder offset changed, add an extra move so everything is continuous
+            if (extruder_offset != m_extruder_offsets[tcr.initial_tool].cast<float>()) {
+                std::ostringstream oss;
+                oss << std::fixed << std::setprecision(3)
+                    << "G1 X" << transformed_pos.x() - extruder_offset.x()
+                    << " Y"   << transformed_pos.y() - extruder_offset.y()
+                    << "\n";
+                gcode_out += oss.str();
+            }
+        }
     }
     return gcode_out;
 }
diff --git a/src/libslic3r/GCode.hpp b/src/libslic3r/GCode.hpp
index 4b81b42aac..f2a67f600b 100644
--- a/src/libslic3r/GCode.hpp
+++ b/src/libslic3r/GCode.hpp
@@ -90,6 +90,7 @@ public:
         m_right(float(/*print_config.wipe_tower_x.value +*/ print_config.wipe_tower_width.value)),
         m_wipe_tower_pos(float(print_config.wipe_tower_x.value), float(print_config.wipe_tower_y.value)),
         m_wipe_tower_rotation(float(print_config.wipe_tower_rotation_angle)),
+        m_extruder_offsets(print_config.extruder_offset.values),
         m_priming(priming),
         m_tool_changes(tool_changes),
         m_final_purge(final_purge),
@@ -107,14 +108,16 @@ private:
     WipeTowerIntegration& operator=(const WipeTowerIntegration&);
     std::string append_tcr(GCode &gcodegen, const WipeTower::ToolChangeResult &tcr, int new_extruder_id) const;
 
-    // Postprocesses gcode: rotates and moves all G1 extrusions and returns result
-    std::string rotate_wipe_tower_moves(const std::string& gcode_original, const Vec2f& start_pos, const Vec2f& translation, float angle) const;
+    // Postprocesses gcode: rotates and moves G1 extrusions and returns result
+    std::string post_process_wipe_tower_moves(const WipeTower::ToolChangeResult& tcr, const Vec2f& translation, float angle) const;
 
     // Left / right edges of the wipe tower, for the planning of wipe moves.
     const float                                                  m_left;
     const float                                                  m_right;
     const Vec2f                                                  m_wipe_tower_pos;
     const float                                                  m_wipe_tower_rotation;
+    const std::vector<Vec2d>                                     m_extruder_offsets;
+
     // Reference to cached values at the Printer class.
     const std::vector<WipeTower::ToolChangeResult>              &m_priming;
     const std::vector<std::vector<WipeTower::ToolChangeResult>> &m_tool_changes;
diff --git a/src/libslic3r/GCode/WipeTower.cpp b/src/libslic3r/GCode/WipeTower.cpp
index 37e4040d19..354ec6d9e1 100644
--- a/src/libslic3r/GCode/WipeTower.cpp
+++ b/src/libslic3r/GCode/WipeTower.cpp
@@ -553,7 +553,7 @@ std::vector<WipeTower::ToolChangeResult> WipeTower::prime(
         result.elapsed_time = writer.elapsed_time();
         result.extrusions 	= writer.extrusions();
         result.start_pos  	= writer.start_pos_rotated();
-        result.end_pos 	  	= writer.pos_rotated();
+        result.end_pos 	  	= writer.pos();
 
         results.push_back(std::move(result));
 
@@ -643,7 +643,7 @@ WipeTower::ToolChangeResult WipeTower::tool_change(unsigned int tool, bool last_
                           m_is_first_layer ? m_filpar[tool].first_layer_temperature : m_filpar[tool].temperature);
         toolchange_Change(writer, tool, m_filpar[tool].material); // Change the tool, set a speed override for soluble and flex materials.
         toolchange_Load(writer, cleaning_box);
-        writer.travel(writer.x(),writer.y()-m_perimeter_width); // cooling and loading were done a bit down the road
+        writer.travel(writer.x(), writer.y()-m_perimeter_width); // cooling and loading were done a bit down the road
         toolchange_Wipe(writer, cleaning_box, wipe_volume);     // Wipe the newly loaded filament until the end of the assigned wipe area.
         ++ m_num_tool_changes;
     } else
diff --git a/src/libslic3r/GCode/WipeTower.hpp b/src/libslic3r/GCode/WipeTower.hpp
index c18a502b13..badb3e8b24 100644
--- a/src/libslic3r/GCode/WipeTower.hpp
+++ b/src/libslic3r/GCode/WipeTower.hpp
@@ -139,13 +139,15 @@ public:
 
         m_perimeter_width = nozzle_diameter * Width_To_Nozzle_Ratio; // all extruders are now assumed to have the same diameter
 
-        std::stringstream stream{m_semm ? ramming_parameters : std::string()};
-        float speed = 0.f;
-        stream >> m_filpar[idx].ramming_line_width_multiplicator >> m_filpar[idx].ramming_step_multiplicator;
-        m_filpar[idx].ramming_line_width_multiplicator /= 100;
-        m_filpar[idx].ramming_step_multiplicator /= 100;
-        while (stream >> speed)
-            m_filpar[idx].ramming_speed.push_back(speed);
+        if (m_semm) {
+            std::stringstream stream{ramming_parameters};
+            float speed = 0.f;
+            stream >> m_filpar[idx].ramming_line_width_multiplicator >> m_filpar[idx].ramming_step_multiplicator;
+            m_filpar[idx].ramming_line_width_multiplicator /= 100;
+            m_filpar[idx].ramming_step_multiplicator /= 100;
+            while (stream >> speed)
+                m_filpar[idx].ramming_speed.push_back(speed);
+        }
 
         m_used_filament_length.resize(std::max(m_used_filament_length.size(), idx + 1)); // makes sure that the vector is big enough so we don't have to check later
 	}
@@ -241,8 +243,8 @@ public:
         int                 cooling_moves = 0;
         float               cooling_initial_speed = 0.f;
         float               cooling_final_speed = 0.f;
-        float               ramming_line_width_multiplicator = 0.f;
-        float               ramming_step_multiplicator = 0.f;
+        float               ramming_line_width_multiplicator = 1.f;
+        float               ramming_step_multiplicator = 1.f;
         float               max_e_speed = std::numeric_limits<float>::max();
         std::vector<float>  ramming_speed;
         float               nozzle_diameter;
diff --git a/src/libslic3r/Model.cpp b/src/libslic3r/Model.cpp
index 66532e9ead..21e1557936 100644
--- a/src/libslic3r/Model.cpp
+++ b/src/libslic3r/Model.cpp
@@ -1971,4 +1971,4 @@ CEREAL_REGISTER_POLYMORPHIC_RELATION(Slic3r::ObjectBase, Slic3r::ModelObject)
 CEREAL_REGISTER_POLYMORPHIC_RELATION(Slic3r::ObjectBase, Slic3r::ModelVolume)
 CEREAL_REGISTER_POLYMORPHIC_RELATION(Slic3r::ObjectBase, Slic3r::ModelInstance)
 CEREAL_REGISTER_POLYMORPHIC_RELATION(Slic3r::ObjectBase, Slic3r::Model)
-#endif
\ No newline at end of file
+#endif
diff --git a/src/libslic3r/Model.hpp b/src/libslic3r/Model.hpp
index 2b4a6d978a..f03d531536 100644
--- a/src/libslic3r/Model.hpp
+++ b/src/libslic3r/Model.hpp
@@ -22,6 +22,8 @@ namespace cereal {
 	class BinaryOutputArchive;
 	template <class T> void load_optional(BinaryInputArchive &ar, std::shared_ptr<const T> &ptr);
 	template <class T> void save_optional(BinaryOutputArchive &ar, const std::shared_ptr<const T> &ptr);
+	template <class T> void load_by_value(BinaryInputArchive &ar, T &obj);
+	template <class T> void save_by_value(BinaryOutputArchive &ar, const T &obj);
 }
 
 namespace Slic3r {
@@ -31,6 +33,7 @@ class ModelInstance;
 class ModelMaterial;
 class ModelObject;
 class ModelVolume;
+class ModelWipeTower;
 class Print;
 class SLAPrint;
 
@@ -66,6 +69,21 @@ private:
 	}
 };
 
+namespace Internal {
+	template<typename T>
+	class StaticSerializationWrapper
+	{
+	public:
+		StaticSerializationWrapper(T &wrap) : wrapped(wrap) {}
+	private:
+		friend class cereal::access;
+		friend class UndoRedo::StackImpl;
+		template<class Archive> void load(Archive &ar) { cereal::load_by_value(ar, wrapped); }
+		template<class Archive> void save(Archive &ar) const { cereal::save_by_value(ar, wrapped); }
+		T&	wrapped;
+	};
+}
+
 typedef std::string t_model_material_id;
 typedef std::string t_model_material_attribute;
 typedef std::map<t_model_material_attribute, std::string> t_model_material_attributes;
@@ -140,7 +158,8 @@ private:
 	ModelMaterial() : ObjectBase(-1), config(-1), m_model(nullptr) { assert(this->id().invalid()); assert(this->config.id().invalid()); }
 	template<class Archive> void serialize(Archive &ar) { 
 		assert(this->id().invalid()); assert(this->config.id().invalid());
-		ar(attributes, config);
+		Internal::StaticSerializationWrapper<ModelConfig> config_wrapper(config);
+		ar(attributes, config_wrapper);
 		// assert(this->id().valid()); assert(this->config.id().valid());
 	}
 
@@ -349,7 +368,8 @@ private:
 	}
 	template<class Archive> void serialize(Archive &ar) {
 		ar(cereal::base_class<ObjectBase>(this));
-		ar(name, input_file, instances, volumes, config, layer_config_ranges, layer_height_profile, sla_support_points, sla_points_status, origin_translation,
+		Internal::StaticSerializationWrapper<ModelConfig> config_wrapper(config);
+		ar(name, input_file, instances, volumes, config_wrapper, layer_config_ranges, layer_height_profile, sla_support_points, sla_points_status, origin_translation,
 			m_bounding_box, m_bounding_box_valid, m_raw_bounding_box, m_raw_bounding_box_valid, m_raw_mesh_bounding_box, m_raw_mesh_bounding_box_valid);
 	}
 };
@@ -535,7 +555,8 @@ private:
 	}
 	template<class Archive> void load(Archive &ar) {
 		bool has_convex_hull;
-		ar(name, config, m_mesh, m_type, m_material_id, m_transformation, m_is_splittable, has_convex_hull);
+		ar(name, m_mesh, m_type, m_material_id, m_transformation, m_is_splittable, has_convex_hull);
+		cereal::load_by_value(ar, config);
 		assert(m_mesh);
 		if (has_convex_hull) {
 			cereal::load_optional(ar, m_convex_hull);
@@ -547,7 +568,8 @@ private:
 	}
 	template<class Archive> void save(Archive &ar) const {
 		bool has_convex_hull = m_convex_hull.get() != nullptr;
-		ar(name, config, m_mesh, m_type, m_material_id, m_transformation, m_is_splittable, has_convex_hull);
+		ar(name, m_mesh, m_type, m_material_id, m_transformation, m_is_splittable, has_convex_hull);
+		cereal::save_by_value(ar, config);
 		if (has_convex_hull)
 			cereal::save_optional(ar, m_convex_hull);
 	}
@@ -650,6 +672,35 @@ private:
 	}
 };
 
+class ModelWipeTower final : public ObjectBase
+{
+public:
+	Vec2d		position;
+	double 		rotation;
+
+private:
+	friend class cereal::access;
+	friend class UndoRedo::StackImpl;
+	friend class Model;
+
+    // Constructors to be only called by derived classes.
+    // Default constructor to assign a unique ID.
+    explicit ModelWipeTower() {}
+    // Constructor with ignored int parameter to assign an invalid ID, to be replaced
+    // by an existing ID copied from elsewhere.
+    explicit ModelWipeTower(int) : ObjectBase(-1) {}
+    // Copy constructor copies the ID.
+	explicit ModelWipeTower(const ModelWipeTower &cfg) = default;
+
+	// Disabled methods.
+	ModelWipeTower(ModelWipeTower &&rhs) = delete;
+	ModelWipeTower& operator=(const ModelWipeTower &rhs) = delete;
+    ModelWipeTower& operator=(ModelWipeTower &&rhs) = delete;
+
+    // For serialization / deserialization of ModelWipeTower composed into another class into the Undo / Redo stack as a separate object.
+    template<typename Archive> void serialize(Archive &ar) { ar(position, rotation); }
+};
+
 // The print bed content.
 // Description of a triangular model with multiple materials, multiple instances with various affine transformations
 // and with multiple modifier meshes.
@@ -665,6 +716,8 @@ public:
     ModelMaterialMap    materials;
     // Objects are owned by a model. Each model may have multiple instances, each instance having its own transformation (shift, scale, rotation).
     ModelObjectPtrs     objects;
+    // Wipe tower object.
+    ModelWipeTower	    wipe_tower;
     
     // Default constructor assigns a new ID to the model.
     Model() { assert(this->id().valid()); }
@@ -742,7 +795,8 @@ private:
 	friend class cereal::access;
 	friend class UndoRedo::StackImpl;
 	template<class Archive> void serialize(Archive &ar) {
-		ar(materials, objects);
+		Internal::StaticSerializationWrapper<ModelWipeTower> wipe_tower_wrapper(wipe_tower);
+		ar(materials, objects, wipe_tower_wrapper);
 	}
 };
 
@@ -778,6 +832,7 @@ void check_model_ids_equal(const Model &model1, const Model &model2);
 namespace cereal
 {
 	template <class Archive> struct specialize<Archive, Slic3r::ModelVolume, cereal::specialization::member_load_save> {};
+	template <class Archive> struct specialize<Archive, Slic3r::ModelConfig, cereal::specialization::member_serialize> {};
 }
 
 #endif /* slic3r_Model_hpp_ */
diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index b4a79c6f04..c61fdca631 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -1121,7 +1121,8 @@ GLCanvas3D::GLCanvas3D(wxGLCanvas* canvas, Bed3D& bed, Camera& camera, GLToolbar
     , m_bed(bed)
     , m_camera(camera)
     , m_view_toolbar(view_toolbar)
-    , m_toolbar(GLToolbar::Normal, "Top")
+    , m_main_toolbar(GLToolbar::Normal, "Top")
+    , m_undoredo_toolbar(GLToolbar::Normal, "Top")
     , m_gizmos(*this)
     , m_use_clipping_planes(false)
     , m_sidebar_field("")
@@ -1228,7 +1229,7 @@ bool GLCanvas3D::init()
         return false;
     }
 
-    if (m_toolbar.is_enabled() && !m_layers_editing.init("variable_layer_height.vs", "variable_layer_height.fs"))
+    if (m_main_toolbar.is_enabled() && !m_layers_editing.init("variable_layer_height.vs", "variable_layer_height.fs"))
     {
         std::cout << "Unable to initialize variable_layer_height shader: please, check that the files variable_layer_height.vs and variable_layer_height.fs are available" << std::endl;
         return false;
@@ -1242,7 +1243,7 @@ bool GLCanvas3D::init()
     if (m_gizmos.is_enabled() && !m_gizmos.init())
         std::cout << "Unable to initialize gizmos: please, check that all the required textures are available" << std::endl;
 
-    if (!_init_toolbar())
+    if (!_init_toolbars())
         return false;
 
     if (m_selection.is_enabled() && !m_selection.init())
@@ -1433,9 +1434,14 @@ void GLCanvas3D::enable_selection(bool enable)
     m_selection.set_enabled(enable);
 }
 
-void GLCanvas3D::enable_toolbar(bool enable)
+void GLCanvas3D::enable_main_toolbar(bool enable)
 {
-    m_toolbar.set_enabled(enable);
+    m_main_toolbar.set_enabled(enable);
+}
+
+void GLCanvas3D::enable_undoredo_toolbar(bool enable)
+{
+    m_undoredo_toolbar.set_enabled(enable);
 }
 
 void GLCanvas3D::enable_dynamic_background(bool enable)
@@ -1771,6 +1777,10 @@ void GLCanvas3D::reload_scene(bool refresh_immediately, bool force_full_scene_re
     PrinterTechnology printer_technology        = m_process->current_printer_technology();
     int               volume_idx_wipe_tower_old = -1;
 
+    if (printer_technology == ptSLA)
+    	// Always do the full refresh in SLA mode to show / hide SLA support structures when an object is moved outside / inside the build volume.
+    	m_regenerate_volumes = true;
+
     if (m_regenerate_volumes)
     {
         // Release invalidated volumes to conserve GPU memory in case of delayed refresh (see m_reload_delayed).
@@ -1803,7 +1813,10 @@ void GLCanvas3D::reload_scene(bool refresh_immediately, bool force_full_scene_re
                             state.step[istep].state = PrintStateBase::INVALID;
                         else
     						for (const ModelInstance *model_instance : print_object->model_object()->instances)
-                                aux_volume_state.emplace_back(state.step[istep].timestamp, model_instance->id());
+    							// Only the instances, which are currently printable, will have the SLA support structures kept.
+    							// The instances outside the print bed will have the GLVolumes of their support structures released.
+    							if (model_instance->is_printable())
+                                	aux_volume_state.emplace_back(state.step[istep].timestamp, model_instance->id());
                     }
 				}
 				sla_support_state.emplace_back(state);
@@ -1955,7 +1968,8 @@ void GLCanvas3D::reload_scene(bool refresh_immediately, bool force_full_scene_re
 
 			// Shift-up all volumes of the object so that it has the right elevation with respect to the print bed
 			for (GLVolume* volume : m_volumes.volumes)
-				volume->set_sla_shift_z(shift_zs[volume->object_idx()]);
+				if (volume->object_idx() < m_model->objects.size() && m_model->objects[volume->object_idx()]->instances[volume->instance_idx()]->is_printable())
+					volume->set_sla_shift_z(shift_zs[volume->object_idx()]);
         }
 
         if (printer_technology == ptFFF && m_config->has("nozzle_diameter"))
@@ -2111,7 +2125,8 @@ void GLCanvas3D::load_sla_preview()
     if ((m_canvas != nullptr) && (print != nullptr))
     {
         _set_current();
-        _load_sla_shells();
+        // Reload the SLA support structures into GLVolumes.
+		this->reload_scene(true, true);
         _update_sla_shells_outside_state();
         _show_warning_texture_if_needed(WarningTexture::SlaSupportsOutside);
     }
@@ -2214,7 +2229,8 @@ void GLCanvas3D::on_idle(wxIdleEvent& evt)
     if (!m_initialized)
         return;
 
-    m_dirty |= m_toolbar.update_items_state();
+    m_dirty |= m_main_toolbar.update_items_state();
+    m_dirty |= m_undoredo_toolbar.update_items_state();
     m_dirty |= m_view_toolbar.update_items_state();
 
     if (!m_dirty)
@@ -2593,7 +2609,15 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
 #endif /* SLIC3R_DEBUG_MOUSE_EVENTS */
 	}
 
-    if (m_toolbar.on_mouse(evt, *this))
+    if (m_main_toolbar.on_mouse(evt, *this))
+    {
+        if (evt.LeftUp() || evt.MiddleUp() || evt.RightUp())
+            mouse_up_cleanup();
+        m_mouse.set_start_position_3D_as_invalid();
+        return;
+    }
+
+    if (m_undoredo_toolbar.on_mouse(evt, *this))
     {
         if (evt.LeftUp() || evt.MiddleUp() || evt.RightUp())
             mouse_up_cleanup();
@@ -2928,13 +2952,16 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
     else if (evt.Moving())
     {
         m_mouse.position = pos.cast<double>();
-        std::string tooltip = "";
+        std::string tooltip = L("");
 
         if (tooltip.empty())
             tooltip = m_gizmos.get_tooltip();
 
         if (tooltip.empty())
-            tooltip = m_toolbar.get_tooltip();
+            tooltip = m_main_toolbar.get_tooltip();
+
+        if (tooltip.empty())
+            tooltip = m_undoredo_toolbar.get_tooltip();
 
         if (tooltip.empty())
             tooltip = m_view_toolbar.get_tooltip();
@@ -3399,16 +3426,19 @@ void GLCanvas3D::_render_undo_redo_stack(const bool is_undo, float pos_x)
     ImGuiWrapper* imgui = wxGetApp().imgui();
 
     const float x = pos_x * (float)get_camera().get_zoom() + 0.5f * (float)get_canvas_size().get_width();
-    imgui->set_next_window_pos(x, m_toolbar.get_height(), ImGuiCond_Always, 0.5f, 0.0f);
+    imgui->set_next_window_pos(x, m_undoredo_toolbar.get_height(), ImGuiCond_Always, 0.5f, 0.0f);
     imgui->set_next_window_bg_alpha(0.5f);
     imgui->begin(wxString::Format(_(L("%s Stack")), stack_name),
                  ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoCollapse);
 
     int hovered = m_imgui_undo_redo_hovered_pos;
     int selected = -1;
-    const float em = static_cast<float>(wxGetApp().em_unit());
+    float em = static_cast<float>(wxGetApp().em_unit());
+#if ENABLE_RETINA_GL
+	em *= m_retina_helper->get_scale_factor();
+#endif
 
-    if (imgui->undo_redo_list(ImVec2(12 * em, 20 * em), is_undo, &string_getter, hovered, selected))
+    if (imgui->undo_redo_list(ImVec2(18 * em, 26 * em), is_undo, &string_getter, hovered, selected))
         m_imgui_undo_redo_hovered_pos = hovered;
     else
         m_imgui_undo_redo_hovered_pos = -1;
@@ -3421,9 +3451,20 @@ void GLCanvas3D::_render_undo_redo_stack(const bool is_undo, float pos_x)
     imgui->end();
 }
 
-bool GLCanvas3D::_init_toolbar()
+bool GLCanvas3D::_init_toolbars()
 {
-    if (!m_toolbar.is_enabled())
+    if (!_init_main_toolbar())
+        return false;
+
+    if (!_init_undoredo_toolbar())
+        return false;
+
+    return true;
+}
+
+bool GLCanvas3D::_init_main_toolbar()
+{
+    if (!m_main_toolbar.is_enabled())
         return true;
 
     BackgroundTexture::Metadata background_data;
@@ -3433,19 +3474,20 @@ bool GLCanvas3D::_init_toolbar()
     background_data.right = 16;
     background_data.bottom = 16;
 
-    if (!m_toolbar.init(background_data))
+    if (!m_main_toolbar.init(background_data))
     {
         // unable to init the toolbar texture, disable it
-        m_toolbar.set_enabled(false);
+        m_main_toolbar.set_enabled(false);
         return true;
     }
 
-//    m_toolbar.set_layout_type(GLToolbar::Layout::Vertical);
-    m_toolbar.set_layout_type(GLToolbar::Layout::Horizontal);
-    m_toolbar.set_layout_orientation(GLToolbar::Layout::Top);
-    m_toolbar.set_border(5.0f);
-    m_toolbar.set_separator_size(5);
-    m_toolbar.set_gap_size(2);
+//    m_main_toolbar.set_layout_type(GLToolbar::Layout::Vertical);
+    m_main_toolbar.set_layout_type(GLToolbar::Layout::Horizontal);
+    m_main_toolbar.set_horizontal_orientation(GLToolbar::Layout::HO_Right);
+    m_main_toolbar.set_vertical_orientation(GLToolbar::Layout::VO_Top);
+    m_main_toolbar.set_border(5.0f);
+    m_main_toolbar.set_separator_size(5);
+    m_main_toolbar.set_gap_size(2);
 
     GLToolbarItem::Data item;
 
@@ -3454,7 +3496,7 @@ bool GLCanvas3D::_init_toolbar()
     item.tooltip = _utf8(L("Add...")) + " [" + GUI::shortkey_ctrl_prefix() + "I]";
     item.sprite_id = 0;
     item.left.action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_ADD)); };
-    if (!m_toolbar.add_item(item))
+    if (!m_main_toolbar.add_item(item))
         return false;
 
     item.name = "delete";
@@ -3463,7 +3505,7 @@ bool GLCanvas3D::_init_toolbar()
     item.sprite_id = 1;
     item.left.action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_DELETE)); };
     item.enabling_callback = []()->bool { return wxGetApp().plater()->can_delete(); };
-    if (!m_toolbar.add_item(item))
+    if (!m_main_toolbar.add_item(item))
         return false;
 
     item.name = "deleteall";
@@ -3472,7 +3514,7 @@ bool GLCanvas3D::_init_toolbar()
     item.sprite_id = 2;
     item.left.action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_DELETE_ALL)); };
     item.enabling_callback = []()->bool { return wxGetApp().plater()->can_delete_all(); };
-    if (!m_toolbar.add_item(item))
+    if (!m_main_toolbar.add_item(item))
         return false;
 
     item.name = "arrange";
@@ -3481,10 +3523,10 @@ bool GLCanvas3D::_init_toolbar()
     item.sprite_id = 3;
     item.left.action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_ARRANGE)); };
     item.enabling_callback = []()->bool { return wxGetApp().plater()->can_arrange(); };
-    if (!m_toolbar.add_item(item))
+    if (!m_main_toolbar.add_item(item))
         return false;
 
-    if (!m_toolbar.add_separator())
+    if (!m_main_toolbar.add_separator())
         return false;
 
     item.name = "copy";
@@ -3493,7 +3535,7 @@ bool GLCanvas3D::_init_toolbar()
     item.sprite_id = 4;
     item.left.action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_COPY)); };
     item.enabling_callback = []()->bool { return wxGetApp().plater()->can_copy_to_clipboard(); };
-    if (!m_toolbar.add_item(item))
+    if (!m_main_toolbar.add_item(item))
         return false;
 
     item.name = "paste";
@@ -3502,10 +3544,10 @@ bool GLCanvas3D::_init_toolbar()
     item.sprite_id = 5;
     item.left.action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_PASTE)); };
     item.enabling_callback = []()->bool { return wxGetApp().plater()->can_paste_from_clipboard(); };
-    if (!m_toolbar.add_item(item))
+    if (!m_main_toolbar.add_item(item))
         return false;
 
-    if (!m_toolbar.add_separator())
+    if (!m_main_toolbar.add_separator())
         return false;
 
     item.name = "more";
@@ -3516,7 +3558,7 @@ bool GLCanvas3D::_init_toolbar()
     item.visibility_callback = []()->bool { return wxGetApp().get_mode() != comSimple; };
     item.enabling_callback = []()->bool { return wxGetApp().plater()->can_increase_instances(); };
 
-    if (!m_toolbar.add_item(item))
+    if (!m_main_toolbar.add_item(item))
         return false;
 
     item.name = "fewer";
@@ -3526,10 +3568,10 @@ bool GLCanvas3D::_init_toolbar()
     item.left.action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_FEWER)); };
     item.visibility_callback = []()->bool { return wxGetApp().get_mode() != comSimple; };
     item.enabling_callback = []()->bool { return wxGetApp().plater()->can_decrease_instances(); };
-    if (!m_toolbar.add_item(item))
+    if (!m_main_toolbar.add_item(item))
         return false;
 
-    if (!m_toolbar.add_separator())
+    if (!m_main_toolbar.add_separator())
         return false;
 
     item.name = "splitobjects";
@@ -3539,7 +3581,7 @@ bool GLCanvas3D::_init_toolbar()
     item.left.action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_SPLIT_OBJECTS)); };
     item.visibility_callback = GLToolbarItem::Default_Visibility_Callback;
     item.enabling_callback = []()->bool { return wxGetApp().plater()->can_split_to_objects(); };
-    if (!m_toolbar.add_item(item))
+    if (!m_main_toolbar.add_item(item))
         return false;
 
     item.name = "splitvolumes";
@@ -3549,10 +3591,10 @@ bool GLCanvas3D::_init_toolbar()
     item.left.action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_SPLIT_VOLUMES)); };
     item.visibility_callback = []()->bool { return wxGetApp().get_mode() != comSimple; };
     item.enabling_callback = []()->bool { return wxGetApp().plater()->can_split_to_volumes(); };
-    if (!m_toolbar.add_item(item))
+    if (!m_main_toolbar.add_item(item))
         return false;
 
-    if (!m_toolbar.add_separator())
+    if (!m_main_toolbar.add_separator())
         return false;
 
     item.name = "layersediting";
@@ -3563,35 +3605,98 @@ bool GLCanvas3D::_init_toolbar()
     item.left.action_callback = [this]() { if (m_canvas != nullptr) wxPostEvent(m_canvas, SimpleEvent(EVT_GLTOOLBAR_LAYERSEDITING)); };
     item.visibility_callback = [this]()->bool { return m_process->current_printer_technology() == ptFFF; };
     item.enabling_callback = []()->bool { return wxGetApp().plater()->can_layers_editing(); };
-    if (!m_toolbar.add_item(item))
+    if (!m_main_toolbar.add_item(item))
         return false;
 
-    if (!m_toolbar.add_separator())
-        return false;
+    return true;
+}
+
+bool GLCanvas3D::_init_undoredo_toolbar()
+{
+    if (!m_undoredo_toolbar.is_enabled())
+        return true;
+
+    BackgroundTexture::Metadata background_data;
+    background_data.filename = "toolbar_background.png";
+    background_data.left = 16;
+    background_data.top = 16;
+    background_data.right = 16;
+    background_data.bottom = 16;
+
+    if (!m_undoredo_toolbar.init(background_data))
+    {
+        // unable to init the toolbar texture, disable it
+        m_undoredo_toolbar.set_enabled(false);
+        return true;
+    }
+
+//    m_undoredo_toolbar.set_layout_type(GLToolbar::Layout::Vertical);
+    m_undoredo_toolbar.set_layout_type(GLToolbar::Layout::Horizontal);
+    m_undoredo_toolbar.set_horizontal_orientation(GLToolbar::Layout::HO_Left);
+    m_undoredo_toolbar.set_vertical_orientation(GLToolbar::Layout::VO_Top);
+    m_undoredo_toolbar.set_border(5.0f);
+    m_undoredo_toolbar.set_separator_size(5);
+    m_undoredo_toolbar.set_gap_size(2);
+
+    GLToolbarItem::Data item;
 
     item.name = "undo";
     item.icon_filename = "undo_toolbar.svg";
     item.tooltip = _utf8(L("Undo")) + " [" + GUI::shortkey_ctrl_prefix() + "Z]";
-    item.sprite_id = 11;
-    item.left.toggable = false;
+    item.sprite_id = 0;
     item.left.action_callback = [this]() { post_event(SimpleEvent(EVT_GLCANVAS_UNDO)); };
     item.right.toggable = true;
     item.right.action_callback = [this]() { m_imgui_undo_redo_hovered_pos = -1; };
     item.right.render_callback = [this](float left, float right, float, float) { if (m_canvas != nullptr) _render_undo_redo_stack(true, 0.5f * (left + right)); };
-    item.visibility_callback = []()->bool { return true; };
-    item.enabling_callback = [this]()->bool { return wxGetApp().plater()->can_undo(); };
-    if (!m_toolbar.add_item(item))
+    item.enabling_callback = [this]()->bool {
+        bool can_undo = wxGetApp().plater()->can_undo();
+        unsigned int id = m_undoredo_toolbar.get_item_id("undo");
+
+        std::string curr_additional_tooltip;
+        m_undoredo_toolbar.get_additional_tooltip(id, curr_additional_tooltip);
+
+        std::string new_additional_tooltip = L("");
+        if (can_undo)
+            wxGetApp().plater()->undo_redo_topmost_string_getter(true, new_additional_tooltip);
+
+        if (new_additional_tooltip != curr_additional_tooltip)
+        {
+            m_undoredo_toolbar.set_additional_tooltip(id, new_additional_tooltip);
+            set_tooltip(L(""));
+        }
+        return can_undo;
+    };
+
+    if (!m_undoredo_toolbar.add_item(item))
         return false;
 
     item.name = "redo";
     item.icon_filename = "redo_toolbar.svg";
     item.tooltip = _utf8(L("Redo")) + " [" + GUI::shortkey_ctrl_prefix() + "Y]";
-    item.sprite_id = 12;
+    item.sprite_id = 1;
     item.left.action_callback = [this]() { post_event(SimpleEvent(EVT_GLCANVAS_REDO)); };
     item.right.action_callback = [this]() { m_imgui_undo_redo_hovered_pos = -1; };
     item.right.render_callback = [this](float left, float right, float, float) { if (m_canvas != nullptr) _render_undo_redo_stack(false, 0.5f * (left + right)); };
-    item.enabling_callback = [this]()->bool { return wxGetApp().plater()->can_redo(); };
-    if (!m_toolbar.add_item(item))
+    item.enabling_callback = [this]()->bool {
+        bool can_redo = wxGetApp().plater()->can_redo();
+        unsigned int id = m_undoredo_toolbar.get_item_id("redo");
+
+        std::string curr_additional_tooltip;
+        m_undoredo_toolbar.get_additional_tooltip(id, curr_additional_tooltip);
+
+        std::string new_additional_tooltip = L("");
+        if (can_redo)
+            wxGetApp().plater()->undo_redo_topmost_string_getter(false, new_additional_tooltip);
+
+        if (new_additional_tooltip != curr_additional_tooltip)
+        {
+            m_undoredo_toolbar.set_additional_tooltip(id, new_additional_tooltip);
+            set_tooltip(L(""));
+        }
+        return can_redo;
+    };
+
+    if (!m_undoredo_toolbar.add_item(item))
         return false;
 
     return true;
@@ -3918,7 +4023,8 @@ void GLCanvas3D::_render_overlays() const
     _render_gizmos_overlay();
     _render_warning_texture();
     _render_legend_texture();
-    _render_toolbar();
+    _render_main_toolbar();
+    _render_undoredo_toolbar();
     _render_view_toolbar();
 
     if ((m_layers_editing.last_object_id >= 0) && (m_layers_editing.object_max_z() > 0.0f))
@@ -4008,64 +4114,57 @@ void GLCanvas3D::_render_gizmos_overlay() const
     m_gizmos.render_overlay();
 }
 
-void GLCanvas3D::_render_toolbar() const
+void GLCanvas3D::_render_main_toolbar() const
 {
+    if (!m_main_toolbar.is_enabled())
+        return;
+
 #if ENABLE_RETINA_GL
-//     m_toolbar.set_scale(m_retina_helper->get_scale_factor());
+//     m_main_toolbar.set_scale(m_retina_helper->get_scale_factor());
     const float scale = m_retina_helper->get_scale_factor() * wxGetApp().toolbar_icon_scale(true);
-    m_toolbar.set_scale(scale); //! #ys_FIXME_experiment
+    m_main_toolbar.set_scale(scale); //! #ys_FIXME_experiment
 #else
-//     m_toolbar.set_scale(m_canvas->GetContentScaleFactor());
-//     m_toolbar.set_scale(wxGetApp().em_unit()*0.1f);
+//     m_main_toolbar.set_scale(m_canvas->GetContentScaleFactor());
+//     m_main_toolbar.set_scale(wxGetApp().em_unit()*0.1f);
     const float size = int(GLToolbar::Default_Icons_Size * wxGetApp().toolbar_icon_scale(true));
-    m_toolbar.set_icons_size(size); //! #ys_FIXME_experiment
+    m_main_toolbar.set_icons_size(size); //! #ys_FIXME_experiment
 #endif // ENABLE_RETINA_GL
 
     Size cnv_size = get_canvas_size();
     float zoom = (float)m_camera.get_zoom();
     float inv_zoom = (zoom != 0.0f) ? 1.0f / zoom : 0.0f;
 
-    GLToolbar::Layout::EOrientation orientation = m_toolbar.get_layout_orientation();
+    float top = 0.5f * (float)cnv_size.get_height() * inv_zoom;
+    float left = -0.5f * (m_main_toolbar.get_width() + m_undoredo_toolbar.get_width()) * inv_zoom;
 
-    float top = 0.0f;
-    float left = 0.0f;
-    switch (m_toolbar.get_layout_type())
-    {
-    default:
-    case GLToolbar::Layout::Horizontal:
-    {
-        // centers the toolbar on the top edge of the 3d scene
-        if (orientation == GLToolbar::Layout::Top)
-        {
-            top = 0.5f * (float)cnv_size.get_height() * inv_zoom;
-            left = -0.5f * m_toolbar.get_width() * inv_zoom;
-        }
-        else
-        {
-            top = (-0.5f * (float)cnv_size.get_height() + m_view_toolbar.get_height()) * inv_zoom;
-            left = -0.5f * m_toolbar.get_width() * inv_zoom;
-        }
-        break;
-    }
-    case GLToolbar::Layout::Vertical:
-    {
-        // centers the toolbar on the right edge of the 3d scene
-        if (orientation == GLToolbar::Layout::Left)
-        {
-            top = 0.5f * m_toolbar.get_height() * inv_zoom;
-            left = (-0.5f * (float)cnv_size.get_width()) * inv_zoom;
-        }
-        else
-        {
-            top = 0.5f * m_toolbar.get_height() * inv_zoom;
-            left = (0.5f * (float)cnv_size.get_width() - m_toolbar.get_width()) * inv_zoom;
-        }
-        break;
-    }
-    }
-    m_toolbar.set_position(top, left);
+    m_main_toolbar.set_position(top, left);
+    m_main_toolbar.render(*this);
+}
 
-    m_toolbar.render(*this);
+void GLCanvas3D::_render_undoredo_toolbar() const
+{
+    if (!m_undoredo_toolbar.is_enabled())
+        return;
+
+#if ENABLE_RETINA_GL
+//     m_undoredo_toolbar.set_scale(m_retina_helper->get_scale_factor());
+    const float scale = m_retina_helper->get_scale_factor() * wxGetApp().toolbar_icon_scale(true);
+    m_undoredo_toolbar.set_scale(scale); //! #ys_FIXME_experiment
+#else
+//     m_undoredo_toolbar.set_scale(m_canvas->GetContentScaleFactor());
+//     m_undoredo_toolbar.set_scale(wxGetApp().em_unit()*0.1f);
+    const float size = int(GLToolbar::Default_Icons_Size * wxGetApp().toolbar_icon_scale(true));
+    m_undoredo_toolbar.set_icons_size(size); //! #ys_FIXME_experiment
+#endif // ENABLE_RETINA_GL
+
+    Size cnv_size = get_canvas_size();
+    float zoom = (float)m_camera.get_zoom();
+    float inv_zoom = (zoom != 0.0f) ? 1.0f / zoom : 0.0f;
+
+    float top = 0.5f * (float)cnv_size.get_height() * inv_zoom;
+    float left = (m_main_toolbar.get_width() - 0.5f * (m_main_toolbar.get_width() + m_undoredo_toolbar.get_width())) * inv_zoom;
+    m_undoredo_toolbar.set_position(top, left);
+    m_undoredo_toolbar.render(*this);
 }
 
 void GLCanvas3D::_render_view_toolbar() const
@@ -5322,56 +5421,6 @@ void GLCanvas3D::_load_fff_shells()
     }
 }
 
-void GLCanvas3D::_load_sla_shells()
-{
-    //FIXME use reload_scene
-#if 1
-    const SLAPrint* print = this->sla_print();
-    if (print->objects().empty())
-        // nothing to render, return
-        return;
-
-    auto add_volume = [this](const SLAPrintObject &object, int volume_id, const SLAPrintObject::Instance& instance,
-        const TriangleMesh &mesh, const float color[4], bool outside_printer_detection_enabled) {
-        m_volumes.volumes.emplace_back(new GLVolume(color));
-        GLVolume& v = *m_volumes.volumes.back();
-        v.indexed_vertex_array.load_mesh(mesh);
-        v.shader_outside_printer_detection_enabled = outside_printer_detection_enabled;
-        v.composite_id.volume_id = volume_id;
-        v.set_instance_offset(unscale(instance.shift(0), instance.shift(1), 0));
-        v.set_instance_rotation(Vec3d(0.0, 0.0, (double)instance.rotation));
-        v.set_instance_mirror(X, object.is_left_handed() ? -1. : 1.);
-        v.set_convex_hull(mesh.convex_hull_3d());
-    };
-
-    // adds objects' volumes 
-    for (const SLAPrintObject* obj : print->objects())
-        if (obj->is_step_done(slaposSliceSupports)) {
-            unsigned int initial_volumes_count = (unsigned int)m_volumes.volumes.size();
-            for (const SLAPrintObject::Instance& instance : obj->instances()) {
-                add_volume(*obj, 0, instance, obj->transformed_mesh(), GLVolume::MODEL_COLOR[0], true);
-                // Set the extruder_id and volume_id to achieve the same color as in the 3D scene when
-                // through the update_volumes_colors_by_extruder() call.
-                m_volumes.volumes.back()->extruder_id = obj->model_object()->volumes.front()->extruder_id();
-                if (obj->is_step_done(slaposSupportTree) && obj->has_mesh(slaposSupportTree))
-                    add_volume(*obj, -int(slaposSupportTree), instance, obj->support_mesh(), GLVolume::SLA_SUPPORT_COLOR, true);
-                if (obj->is_step_done(slaposBasePool) && obj->has_mesh(slaposBasePool))
-                    add_volume(*obj, -int(slaposBasePool), instance, obj->pad_mesh(), GLVolume::SLA_PAD_COLOR, false);
-            }
-            double shift_z = obj->get_current_elevation();
-            for (unsigned int i = initial_volumes_count; i < m_volumes.volumes.size(); ++ i) {
-                GLVolume& v = *m_volumes.volumes[i];
-                // apply shift z
-                v.set_sla_shift_z(shift_z);
-            }
-        }
-
-    update_volumes_colors_by_extruder();
-#else
-    this->reload_scene(true, true);
-#endif
-}
-
 void GLCanvas3D::_update_gcode_volumes_visibility(const GCodePreviewData& preview_data)
 {
     unsigned int size = (unsigned int)m_gcode_preview_volume_index.first_volumes.size();
@@ -5587,14 +5636,14 @@ void GLCanvas3D::_update_selection_from_hover()
 
 bool GLCanvas3D::_deactivate_undo_redo_toolbar_items()
 {
-    if (m_toolbar.is_item_pressed("undo"))
+    if (m_undoredo_toolbar.is_item_pressed("undo"))
     {
-        m_toolbar.force_right_action(m_toolbar.get_item_id("undo"), *this);
+        m_undoredo_toolbar.force_right_action(m_undoredo_toolbar.get_item_id("undo"), *this);
         return true;
     }
-    else if (m_toolbar.is_item_pressed("redo"))
+    else if (m_undoredo_toolbar.is_item_pressed("redo"))
     {
-        m_toolbar.force_right_action(m_toolbar.get_item_id("redo"), *this);
+        m_undoredo_toolbar.force_right_action(m_undoredo_toolbar.get_item_id("redo"), *this);
         return true;
     }
 
diff --git a/src/slic3r/GUI/GLCanvas3D.hpp b/src/slic3r/GUI/GLCanvas3D.hpp
index cdf45c4f7c..b6f0843a22 100644
--- a/src/slic3r/GUI/GLCanvas3D.hpp
+++ b/src/slic3r/GUI/GLCanvas3D.hpp
@@ -412,7 +412,8 @@ private:
     Shader m_shader;
     Mouse m_mouse;
     mutable GLGizmosManager m_gizmos;
-    mutable GLToolbar m_toolbar;
+    mutable GLToolbar m_main_toolbar;
+    mutable GLToolbar m_undoredo_toolbar;
     ClippingPlane m_clipping_planes[2];
     mutable ClippingPlane m_camera_clipping_plane;
     bool m_use_clipping_planes;
@@ -525,7 +526,8 @@ public:
     void enable_moving(bool enable);
     void enable_gizmos(bool enable);
     void enable_selection(bool enable);
-    void enable_toolbar(bool enable);
+    void enable_main_toolbar(bool enable);
+    void enable_undoredo_toolbar(bool enable);
     void enable_dynamic_background(bool enable);
     void allow_multisample(bool allow);
 
@@ -618,10 +620,18 @@ public:
     void start_keeping_dirty() { m_keep_dirty = true; }
     void stop_keeping_dirty() { m_keep_dirty = false; }
 
+    unsigned int get_main_toolbar_item_id(const std::string& name) const { return m_main_toolbar.get_item_id(name); }
+    void force_main_toolbar_left_action(unsigned int item_id) { m_main_toolbar.force_left_action(item_id, *this); }
+    void force_main_toolbar_right_action(unsigned int item_id) { m_main_toolbar.force_right_action(item_id, *this); }
+    void get_undoredo_toolbar_additional_tooltip(unsigned int item_id, std::string& text) { return m_undoredo_toolbar.get_additional_tooltip(item_id, text); }
+    void set_undoredo_toolbar_additional_tooltip(unsigned int item_id, const std::string& text) { m_undoredo_toolbar.set_additional_tooltip(item_id, text); }
+
 private:
     bool _is_shown_on_screen() const;
 
-    bool _init_toolbar();
+    bool _init_toolbars();
+    bool _init_main_toolbar();
+    bool _init_undoredo_toolbar();
 
     bool _set_current();
     void _resize(unsigned int w, unsigned int h);
@@ -648,7 +658,8 @@ private:
     void _render_volumes_for_picking() const;
     void _render_current_gizmo() const;
     void _render_gizmos_overlay() const;
-    void _render_toolbar() const;
+    void _render_main_toolbar() const;
+    void _render_undoredo_toolbar() const;
     void _render_view_toolbar() const;
 #if ENABLE_SHOW_CAMERA_TARGET
     void _render_camera_target() const;
@@ -695,8 +706,6 @@ private:
     void _load_gcode_unretractions(const GCodePreviewData& preview_data);
     // generates objects and wipe tower geometry
     void _load_fff_shells();
-    // generates objects geometry for sla
-    void _load_sla_shells();
     // sets gcode geometry visibility according to user selection
     void _update_gcode_volumes_visibility(const GCodePreviewData& preview_data);
     void _update_toolpath_volumes_outside_state();
diff --git a/src/slic3r/GUI/GLToolbar.cpp b/src/slic3r/GUI/GLToolbar.cpp
index f4748f680e..63387bf2db 100644
--- a/src/slic3r/GUI/GLToolbar.cpp
+++ b/src/slic3r/GUI/GLToolbar.cpp
@@ -48,6 +48,7 @@ GLToolbarItem::Data::Data()
     : name("")
     , icon_filename("")
     , tooltip("")
+    , additional_tooltip("")
     , sprite_id(-1)
     , visible(true)
     , visibility_callback(Default_Visibility_Callback)
@@ -131,7 +132,8 @@ const float GLToolbar::Default_Icons_Size = 40.0f;
 
 GLToolbar::Layout::Layout()
     : type(Horizontal)
-    , orientation(Center)
+    , horizontal_orientation(HO_Center)
+    , vertical_orientation(VO_Center)
     , top(0.0f)
     , left(0.0f)
     , border(0.0f)
@@ -191,16 +193,6 @@ void GLToolbar::set_layout_type(GLToolbar::Layout::EType type)
     m_layout.dirty = true;
 }
 
-GLToolbar::Layout::EOrientation GLToolbar::get_layout_orientation() const
-{
-    return m_layout.orientation;
-}
-
-void GLToolbar::set_layout_orientation(GLToolbar::Layout::EOrientation orientation)
-{
-    m_layout.orientation = orientation;
-}
-
 void GLToolbar::set_position(float top, float left)
 {
     m_layout.top = top;
@@ -374,6 +366,31 @@ void GLToolbar::force_right_action(unsigned int item_id, GLCanvas3D& parent)
     do_action(GLToolbarItem::Right, item_id, parent, false);
 }
 
+void GLToolbar::get_additional_tooltip(unsigned int item_id, std::string& text)
+{
+    if (item_id < (unsigned int)m_items.size())
+    {
+        GLToolbarItem* item = m_items[item_id];
+        if (item != nullptr)
+        {
+            text = item->get_additional_tooltip();
+            return;
+        }
+    }
+
+    text = L("");
+}
+
+void GLToolbar::set_additional_tooltip(unsigned int item_id, const std::string& text)
+{
+    if (item_id < (unsigned int)m_items.size())
+    {
+        GLToolbarItem* item = m_items[item_id];
+        if (item != nullptr)
+            item->set_additional_tooltip(text);
+    }
+}
+
 bool GLToolbar::update_items_state()
 {
     bool ret = false;
@@ -403,6 +420,9 @@ void GLToolbar::render(const GLCanvas3D& parent) const
 
 bool GLToolbar::on_mouse(wxMouseEvent& evt, GLCanvas3D& parent)
 {
+    if (!m_enabled)
+        return false;
+
     Vec2d mouse_pos((double)evt.GetX(), (double)evt.GetY());
     bool processed = false;
 
@@ -433,7 +453,7 @@ bool GLToolbar::on_mouse(wxMouseEvent& evt, GLCanvas3D& parent)
     if (item_id == -1)
     {
         // mouse is outside the toolbar
-        m_tooltip = "";
+        m_tooltip = L("");
     }
     else
     {
@@ -600,7 +620,7 @@ void GLToolbar::do_action(GLToolbarItem::EActionType type, unsigned int item_id,
 std::string GLToolbar::update_hover_state(const Vec2d& mouse_pos, GLCanvas3D& parent)
 {
     if (!m_enabled)
-        return "";
+        return L("");
 
     switch (m_layout.type)
     {
@@ -649,7 +669,15 @@ std::string GLToolbar::update_hover_state_horizontal(const Vec2d& mouse_pos, GLC
             GLToolbarItem::EState state = item->get_state();
             bool inside = (left <= (float)scaled_mouse_pos(0)) && ((float)scaled_mouse_pos(0) <= right) && (bottom <= (float)scaled_mouse_pos(1)) && ((float)scaled_mouse_pos(1) <= top);
             if (inside)
+            {
                 tooltip = item->get_tooltip();
+                if (!item->is_pressed())
+                {
+                    const std::string& additional_tooltip = item->get_additional_tooltip();
+                    if (!additional_tooltip.empty())
+                        tooltip += L("\n") + additional_tooltip;
+                }
+            }
 
             switch (state)
             {
@@ -745,7 +773,15 @@ std::string GLToolbar::update_hover_state_vertical(const Vec2d& mouse_pos, GLCan
             GLToolbarItem::EState state = item->get_state();
             bool inside = (left <= (float)scaled_mouse_pos(0)) && ((float)scaled_mouse_pos(0) <= right) && (bottom <= (float)scaled_mouse_pos(1)) && ((float)scaled_mouse_pos(1) <= top);
             if (inside)
+            {
                 tooltip = item->get_tooltip();
+                if (!item->is_pressed())
+                {
+                    const std::string& additional_tooltip = item->get_additional_tooltip();
+                    if (!additional_tooltip.empty())
+                        tooltip += L("\n") + additional_tooltip;
+                }
+            }
 
             switch (state)
             {
@@ -966,6 +1002,84 @@ int GLToolbar::contains_mouse_vertical(const Vec2d& mouse_pos, const GLCanvas3D&
     return -1;
 }
 
+void GLToolbar::render_background(float left, float top, float right, float bottom, float border) const
+{
+    unsigned int tex_id = m_background_texture.texture.get_id();
+    float tex_width = (float)m_background_texture.texture.get_width();
+    float tex_height = (float)m_background_texture.texture.get_height();
+    if ((tex_id != 0) && (tex_width > 0) && (tex_height > 0))
+    {
+        float inv_tex_width = (tex_width != 0.0f) ? 1.0f / tex_width : 0.0f;
+        float inv_tex_height = (tex_height != 0.0f) ? 1.0f / tex_height : 0.0f;
+
+        float internal_left = left + border;
+        float internal_right = right - border;
+        float internal_top = top - border;
+        float internal_bottom = bottom + border;
+
+        float left_uv = 0.0f;
+        float right_uv = 1.0f;
+        float top_uv = 1.0f;
+        float bottom_uv = 0.0f;
+
+        float internal_left_uv = (float)m_background_texture.metadata.left * inv_tex_width;
+        float internal_right_uv = 1.0f - (float)m_background_texture.metadata.right * inv_tex_width;
+        float internal_top_uv = 1.0f - (float)m_background_texture.metadata.top * inv_tex_height;
+        float internal_bottom_uv = (float)m_background_texture.metadata.bottom * inv_tex_height;
+
+        // top-left corner
+        if ((m_layout.horizontal_orientation == Layout::HO_Left) || (m_layout.vertical_orientation == Layout::VO_Top))
+            GLTexture::render_sub_texture(tex_id, left, internal_left, internal_top, top, { { internal_left_uv, internal_bottom_uv }, { internal_right_uv, internal_bottom_uv }, { internal_right_uv, internal_top_uv }, { internal_left_uv, internal_top_uv } });
+        else
+            GLTexture::render_sub_texture(tex_id, left, internal_left, internal_top, top, { { left_uv, internal_top_uv }, { internal_left_uv, internal_top_uv }, { internal_left_uv, top_uv }, { left_uv, top_uv } });
+
+        // top edge
+        if (m_layout.vertical_orientation == Layout::VO_Top)
+            GLTexture::render_sub_texture(tex_id, internal_left, internal_right, internal_top, top, { { internal_left_uv, internal_bottom_uv }, { internal_right_uv, internal_bottom_uv }, { internal_right_uv, internal_top_uv }, { internal_left_uv, internal_top_uv } });
+        else
+            GLTexture::render_sub_texture(tex_id, internal_left, internal_right, internal_top, top, { { internal_left_uv, internal_top_uv }, { internal_right_uv, internal_top_uv }, { internal_right_uv, top_uv }, { internal_left_uv, top_uv } });
+
+        // top-right corner
+        if ((m_layout.horizontal_orientation == Layout::HO_Right) || (m_layout.vertical_orientation == Layout::VO_Top))
+            GLTexture::render_sub_texture(tex_id, internal_right, right, internal_top, top, { { internal_left_uv, internal_bottom_uv }, { internal_right_uv, internal_bottom_uv }, { internal_right_uv, internal_top_uv }, { internal_left_uv, internal_top_uv } });
+        else
+            GLTexture::render_sub_texture(tex_id, internal_right, right, internal_top, top, { { internal_right_uv, internal_top_uv }, { right_uv, internal_top_uv }, { right_uv, top_uv }, { internal_right_uv, top_uv } });
+
+        // center-left edge
+        if (m_layout.horizontal_orientation == Layout::HO_Left)
+            GLTexture::render_sub_texture(tex_id, left, internal_left, internal_bottom, internal_top, { { internal_left_uv, internal_bottom_uv }, { internal_right_uv, internal_bottom_uv }, { internal_right_uv, internal_top_uv }, { internal_left_uv, internal_top_uv } });
+        else
+            GLTexture::render_sub_texture(tex_id, left, internal_left, internal_bottom, internal_top, { { left_uv, internal_bottom_uv }, { internal_left_uv, internal_bottom_uv }, { internal_left_uv, internal_top_uv }, { left_uv, internal_top_uv } });
+
+        // center
+        GLTexture::render_sub_texture(tex_id, internal_left, internal_right, internal_bottom, internal_top, { { internal_left_uv, internal_bottom_uv }, { internal_right_uv, internal_bottom_uv }, { internal_right_uv, internal_top_uv }, { internal_left_uv, internal_top_uv } });
+
+        // center-right edge
+        if (m_layout.horizontal_orientation == Layout::HO_Right)
+            GLTexture::render_sub_texture(tex_id, internal_right, right, internal_bottom, internal_top, { { internal_left_uv, internal_bottom_uv }, { internal_right_uv, internal_bottom_uv }, { internal_right_uv, internal_top_uv }, { internal_left_uv, internal_top_uv } });
+        else
+            GLTexture::render_sub_texture(tex_id, internal_right, right, internal_bottom, internal_top, { { internal_right_uv, internal_bottom_uv }, { right_uv, internal_bottom_uv }, { right_uv, internal_top_uv }, { internal_right_uv, internal_top_uv } });
+
+        // bottom-left corner
+        if ((m_layout.horizontal_orientation == Layout::HO_Left) || (m_layout.vertical_orientation == Layout::VO_Bottom))
+            GLTexture::render_sub_texture(tex_id, left, internal_left, bottom, internal_bottom, { { internal_left_uv, internal_bottom_uv }, { internal_right_uv, internal_bottom_uv }, { internal_right_uv, internal_top_uv }, { internal_left_uv, internal_top_uv } });
+        else
+            GLTexture::render_sub_texture(tex_id, left, internal_left, bottom, internal_bottom, { { left_uv, bottom_uv }, { internal_left_uv, bottom_uv }, { internal_left_uv, internal_bottom_uv }, { left_uv, internal_bottom_uv } });
+
+        // bottom edge
+        if (m_layout.vertical_orientation == Layout::VO_Bottom)
+            GLTexture::render_sub_texture(tex_id, internal_left, internal_right, bottom, internal_bottom, { { internal_left_uv, internal_bottom_uv }, { internal_right_uv, internal_bottom_uv }, { internal_right_uv, internal_top_uv }, { internal_left_uv, internal_top_uv } });
+        else
+            GLTexture::render_sub_texture(tex_id, internal_left, internal_right, bottom, internal_bottom, { { internal_left_uv, bottom_uv }, { internal_right_uv, bottom_uv }, { internal_right_uv, internal_bottom_uv }, { internal_left_uv, internal_bottom_uv } });
+
+        // bottom-right corner
+        if ((m_layout.horizontal_orientation == Layout::HO_Right) || (m_layout.vertical_orientation == Layout::VO_Bottom))
+            GLTexture::render_sub_texture(tex_id, internal_right, right, bottom, internal_bottom, { { internal_left_uv, internal_bottom_uv }, { internal_right_uv, internal_bottom_uv }, { internal_right_uv, internal_top_uv }, { internal_left_uv, internal_top_uv } });
+        else
+            GLTexture::render_sub_texture(tex_id, internal_right, right, bottom, internal_bottom, { { internal_right_uv, bottom_uv }, { right_uv, bottom_uv }, { right_uv, internal_bottom_uv }, { internal_right_uv, internal_bottom_uv } });
+    }
+}
+
 void GLToolbar::render_horizontal(const GLCanvas3D& parent) const
 {
     unsigned int tex_id = m_icons_texture.get_id();
@@ -991,88 +1105,7 @@ void GLToolbar::render_horizontal(const GLCanvas3D& parent) const
     float right = left + scaled_width;
     float bottom = top - scaled_height;
 
-    // renders background
-    unsigned int bg_tex_id = m_background_texture.texture.get_id();
-    float bg_tex_width = (float)m_background_texture.texture.get_width();
-    float bg_tex_height = (float)m_background_texture.texture.get_height();
-    if ((bg_tex_id != 0) && (bg_tex_width > 0) && (bg_tex_height > 0))
-    {
-        float inv_bg_tex_width = (bg_tex_width != 0.0f) ? 1.0f / bg_tex_width : 0.0f;
-        float inv_bg_tex_height = (bg_tex_height != 0.0f) ? 1.0f / bg_tex_height : 0.0f;
-
-        float bg_uv_left = 0.0f;
-        float bg_uv_right = 1.0f;
-        float bg_uv_top = 1.0f;
-        float bg_uv_bottom = 0.0f;
-
-        float bg_left = left;
-        float bg_right = right;
-        float bg_top = top;
-        float bg_bottom = bottom;
-        float bg_width = right - left;
-        float bg_height = top - bottom;
-        float bg_min_size = std::min(bg_width, bg_height);
-
-        float bg_uv_i_left = (float)m_background_texture.metadata.left * inv_bg_tex_width;
-        float bg_uv_i_right = 1.0f - (float)m_background_texture.metadata.right * inv_bg_tex_width;
-        float bg_uv_i_top = 1.0f - (float)m_background_texture.metadata.top * inv_bg_tex_height;
-        float bg_uv_i_bottom = (float)m_background_texture.metadata.bottom * inv_bg_tex_height;
-
-        float bg_i_left = bg_left + scaled_border;
-        float bg_i_right = bg_right - scaled_border;
-        float bg_i_top = bg_top - scaled_border;
-        float bg_i_bottom = bg_bottom + scaled_border;
-
-        switch (m_layout.orientation)
-        {
-        case Layout::Top:
-        {
-            bg_uv_top = bg_uv_i_top;
-            bg_i_top = bg_top;
-            break;
-        }
-        case Layout::Bottom:
-        {
-            bg_uv_bottom = bg_uv_i_bottom;
-            bg_i_bottom = bg_bottom;
-            break;
-        }
-        case Layout::Center:
-        {
-            break;
-        }
-        };
-
-        if ((m_layout.border > 0) && (bg_uv_top != bg_uv_i_top))
-        {
-            if (bg_uv_left != bg_uv_i_left)
-                GLTexture::render_sub_texture(bg_tex_id, bg_left, bg_i_left, bg_i_top, bg_top, { { bg_uv_left, bg_uv_i_top }, { bg_uv_i_left, bg_uv_i_top }, { bg_uv_i_left, bg_uv_top }, { bg_uv_left, bg_uv_top } });
-
-            GLTexture::render_sub_texture(bg_tex_id, bg_i_left, bg_i_right, bg_i_top, bg_top, { { bg_uv_i_left, bg_uv_i_top }, { bg_uv_i_right, bg_uv_i_top }, { bg_uv_i_right, bg_uv_top }, { bg_uv_i_left, bg_uv_top } });
-
-            if (bg_uv_right != bg_uv_i_right)
-                GLTexture::render_sub_texture(bg_tex_id, bg_i_right, bg_right, bg_i_top, bg_top, { { bg_uv_i_right, bg_uv_i_top }, { bg_uv_right, bg_uv_i_top }, { bg_uv_right, bg_uv_top }, { bg_uv_i_right, bg_uv_top } });
-        }
-
-        if ((m_layout.border > 0) && (bg_uv_left != bg_uv_i_left))
-            GLTexture::render_sub_texture(bg_tex_id, bg_left, bg_i_left, bg_i_bottom, bg_i_top, { { bg_uv_left, bg_uv_i_bottom }, { bg_uv_i_left, bg_uv_i_bottom }, { bg_uv_i_left, bg_uv_i_top }, { bg_uv_left, bg_uv_i_top } });
-
-        GLTexture::render_sub_texture(bg_tex_id, bg_i_left, bg_i_right, bg_i_bottom, bg_i_top, { { bg_uv_i_left, bg_uv_i_bottom }, { bg_uv_i_right, bg_uv_i_bottom }, { bg_uv_i_right, bg_uv_i_top }, { bg_uv_i_left, bg_uv_i_top } });
-
-        if ((m_layout.border > 0) && (bg_uv_right != bg_uv_i_right))
-            GLTexture::render_sub_texture(bg_tex_id, bg_i_right, bg_right, bg_i_bottom, bg_i_top, { { bg_uv_i_right, bg_uv_i_bottom }, { bg_uv_right, bg_uv_i_bottom }, { bg_uv_right, bg_uv_i_top }, { bg_uv_i_right, bg_uv_i_top } });
-
-        if ((m_layout.border > 0) && (bg_uv_bottom != bg_uv_i_bottom))
-        {
-            if (bg_uv_left != bg_uv_i_left)
-                GLTexture::render_sub_texture(bg_tex_id, bg_left, bg_i_left, bg_bottom, bg_i_bottom, { { bg_uv_left, bg_uv_bottom }, { bg_uv_i_left, bg_uv_bottom }, { bg_uv_i_left, bg_uv_i_bottom }, { bg_uv_left, bg_uv_i_bottom } });
-
-            GLTexture::render_sub_texture(bg_tex_id, bg_i_left, bg_i_right, bg_bottom, bg_i_bottom, { { bg_uv_i_left, bg_uv_bottom }, { bg_uv_i_right, bg_uv_bottom }, { bg_uv_i_right, bg_uv_i_bottom }, { bg_uv_i_left, bg_uv_i_bottom } });
-
-            if (bg_uv_right != bg_uv_i_right)
-                GLTexture::render_sub_texture(bg_tex_id, bg_i_right, bg_right, bg_bottom, bg_i_bottom, { { bg_uv_i_right, bg_uv_bottom }, { bg_uv_right, bg_uv_bottom }, { bg_uv_right, bg_uv_i_bottom }, { bg_uv_i_right, bg_uv_i_bottom } });
-        }
-    }
+    render_background(left, top, right, bottom, scaled_border);
 
     left += scaled_border;
     top -= scaled_border;
@@ -1121,88 +1154,7 @@ void GLToolbar::render_vertical(const GLCanvas3D& parent) const
     float right = left + scaled_width;
     float bottom = top - scaled_height;
 
-    // renders background
-    unsigned int bg_tex_id = m_background_texture.texture.get_id();
-    float bg_tex_width = (float)m_background_texture.texture.get_width();
-    float bg_tex_height = (float)m_background_texture.texture.get_height();
-    if ((bg_tex_id != 0) && (bg_tex_width > 0) && (bg_tex_height > 0))
-    {
-        float inv_bg_tex_width = (bg_tex_width != 0.0f) ? 1.0f / bg_tex_width : 0.0f;
-        float inv_bg_tex_height = (bg_tex_height != 0.0f) ? 1.0f / bg_tex_height : 0.0f;
-
-        float bg_uv_left = 0.0f;
-        float bg_uv_right = 1.0f;
-        float bg_uv_top = 1.0f;
-        float bg_uv_bottom = 0.0f;
-
-        float bg_left = left;
-        float bg_right = right;
-        float bg_top = top;
-        float bg_bottom = bottom;
-        float bg_width = right - left;
-        float bg_height = top - bottom;
-        float bg_min_size = std::min(bg_width, bg_height);
-
-        float bg_uv_i_left = (float)m_background_texture.metadata.left * inv_bg_tex_width;
-        float bg_uv_i_right = 1.0f - (float)m_background_texture.metadata.right * inv_bg_tex_width;
-        float bg_uv_i_top = 1.0f - (float)m_background_texture.metadata.top * inv_bg_tex_height;
-        float bg_uv_i_bottom = (float)m_background_texture.metadata.bottom * inv_bg_tex_height;
-
-        float bg_i_left = bg_left + scaled_border;
-        float bg_i_right = bg_right - scaled_border;
-        float bg_i_top = bg_top - scaled_border;
-        float bg_i_bottom = bg_bottom + scaled_border;
-
-        switch (m_layout.orientation)
-        {
-        case Layout::Left:
-        {
-            bg_uv_left = bg_uv_i_left;
-            bg_i_left = bg_left;
-            break;
-        }
-        case Layout::Right:
-        {
-            bg_uv_right = bg_uv_i_right;
-            bg_i_right = bg_right;
-            break;
-        }
-        case Layout::Center:
-        {
-            break;
-        }
-        };
-
-        if ((m_layout.border > 0) && (bg_uv_top != bg_uv_i_top))
-        {
-            if (bg_uv_left != bg_uv_i_left)
-                GLTexture::render_sub_texture(bg_tex_id, bg_left, bg_i_left, bg_i_top, bg_top, { { bg_uv_left, bg_uv_i_top }, { bg_uv_i_left, bg_uv_i_top }, { bg_uv_i_left, bg_uv_top }, { bg_uv_left, bg_uv_top } });
-
-            GLTexture::render_sub_texture(bg_tex_id, bg_i_left, bg_i_right, bg_i_top, bg_top, { { bg_uv_i_left, bg_uv_i_top }, { bg_uv_i_right, bg_uv_i_top }, { bg_uv_i_right, bg_uv_top }, { bg_uv_i_left, bg_uv_top } });
-
-            if (bg_uv_right != bg_uv_i_right)
-                GLTexture::render_sub_texture(bg_tex_id, bg_i_right, bg_right, bg_i_top, bg_top, { { bg_uv_i_right, bg_uv_i_top }, { bg_uv_right, bg_uv_i_top }, { bg_uv_right, bg_uv_top }, { bg_uv_i_right, bg_uv_top } });
-        }
-
-        if ((m_layout.border > 0) && (bg_uv_left != bg_uv_i_left))
-            GLTexture::render_sub_texture(bg_tex_id, bg_left, bg_i_left, bg_i_bottom, bg_i_top, { { bg_uv_left, bg_uv_i_bottom }, { bg_uv_i_left, bg_uv_i_bottom }, { bg_uv_i_left, bg_uv_i_top }, { bg_uv_left, bg_uv_i_top } });
-
-        GLTexture::render_sub_texture(bg_tex_id, bg_i_left, bg_i_right, bg_i_bottom, bg_i_top, { { bg_uv_i_left, bg_uv_i_bottom }, { bg_uv_i_right, bg_uv_i_bottom }, { bg_uv_i_right, bg_uv_i_top }, { bg_uv_i_left, bg_uv_i_top } });
-
-        if ((m_layout.border > 0) && (bg_uv_right != bg_uv_i_right))
-            GLTexture::render_sub_texture(bg_tex_id, bg_i_right, bg_right, bg_i_bottom, bg_i_top, { { bg_uv_i_right, bg_uv_i_bottom }, { bg_uv_right, bg_uv_i_bottom }, { bg_uv_right, bg_uv_i_top }, { bg_uv_i_right, bg_uv_i_top } });
-
-        if ((m_layout.border > 0) && (bg_uv_bottom != bg_uv_i_bottom))
-        {
-            if (bg_uv_left != bg_uv_i_left)
-                GLTexture::render_sub_texture(bg_tex_id, bg_left, bg_i_left, bg_bottom, bg_i_bottom, { { bg_uv_left, bg_uv_bottom }, { bg_uv_i_left, bg_uv_bottom }, { bg_uv_i_left, bg_uv_i_bottom }, { bg_uv_left, bg_uv_i_bottom } });
-
-            GLTexture::render_sub_texture(bg_tex_id, bg_i_left, bg_i_right, bg_bottom, bg_i_bottom, { { bg_uv_i_left, bg_uv_bottom }, { bg_uv_i_right, bg_uv_bottom }, { bg_uv_i_right, bg_uv_i_bottom }, { bg_uv_i_left, bg_uv_i_bottom } });
-
-            if (bg_uv_right != bg_uv_i_right)
-                GLTexture::render_sub_texture(bg_tex_id, bg_i_right, bg_right, bg_bottom, bg_i_bottom, { { bg_uv_i_right, bg_uv_bottom }, { bg_uv_right, bg_uv_bottom }, { bg_uv_right, bg_uv_i_bottom }, { bg_uv_i_right, bg_uv_i_bottom } });
-        }
-    }
+    render_background(left, top, right, bottom, scaled_border);
 
     left += scaled_border;
     top -= scaled_border;
diff --git a/src/slic3r/GUI/GLToolbar.hpp b/src/slic3r/GUI/GLToolbar.hpp
index 875b2f9f69..527317e589 100644
--- a/src/slic3r/GUI/GLToolbar.hpp
+++ b/src/slic3r/GUI/GLToolbar.hpp
@@ -80,6 +80,7 @@ public:
         std::string name;
         std::string icon_filename;
         std::string tooltip;
+        std::string additional_tooltip;
         unsigned int sprite_id;
         // mouse left click
         Option left;
@@ -112,6 +113,8 @@ public:
     const std::string& get_name() const { return m_data.name; }
     const std::string& get_icon_filename() const { return m_data.icon_filename; }
     const std::string& get_tooltip() const { return m_data.tooltip; }
+    const std::string& get_additional_tooltip() const { return m_data.additional_tooltip; }
+    void set_additional_tooltip(const std::string& text) { m_data.additional_tooltip = text; }
 
     void do_left_action() { m_last_action_type = Left; m_data.left.action_callback(); }
     void do_right_action() { m_last_action_type = Right; m_data.right.action_callback(); }
@@ -189,18 +192,25 @@ public:
             Num_Types
         };
 
-        enum EOrientation : unsigned int
+        enum EHorizontalOrientation : unsigned char
         {
-            Top,
-            Bottom,
-            Left,
-            Right,
-            Center,
-            Num_Locations
+            HO_Left,
+            HO_Center,
+            HO_Right,
+            Num_Horizontal_Orientations
+        };
+
+        enum EVerticalOrientation : unsigned char
+        {
+            VO_Top,
+            VO_Center,
+            VO_Bottom,
+            Num_Vertical_Orientations
         };
 
         EType type;
-        EOrientation orientation;
+        EHorizontalOrientation horizontal_orientation;
+        EVerticalOrientation vertical_orientation;
         float top;
         float left;
         float border;
@@ -254,8 +264,10 @@ public:
 
     Layout::EType get_layout_type() const;
     void set_layout_type(Layout::EType type);
-    Layout::EOrientation get_layout_orientation() const;
-    void set_layout_orientation(Layout::EOrientation orientation);
+    Layout::EHorizontalOrientation get_horizontal_orientation() const { return m_layout.horizontal_orientation; }
+    void set_horizontal_orientation(Layout::EHorizontalOrientation orientation) { m_layout.horizontal_orientation = orientation; }
+    Layout::EVerticalOrientation get_vertical_orientation() const { return m_layout.vertical_orientation; }
+    void set_vertical_orientation(Layout::EVerticalOrientation orientation) { m_layout.vertical_orientation = orientation; }
 
     void set_position(float top, float left);
     void set_border(float border);
@@ -288,6 +300,9 @@ public:
 
     const std::string& get_tooltip() const { return m_tooltip; }
 
+    void get_additional_tooltip(unsigned int item_id, std::string& text);
+    void set_additional_tooltip(unsigned int item_id, const std::string& text);
+
     // returns true if any item changed its state
     bool update_items_state();
 
@@ -311,6 +326,7 @@ private:
     int contains_mouse_horizontal(const Vec2d& mouse_pos, const GLCanvas3D& parent) const;
     int contains_mouse_vertical(const Vec2d& mouse_pos, const GLCanvas3D& parent) const;
 
+    void render_background(float left, float top, float right, float bottom, float border) const;
     void render_horizontal(const GLCanvas3D& parent) const;
     void render_vertical(const GLCanvas3D& parent) const;
 
diff --git a/src/slic3r/GUI/GUI_ObjectManipulation.cpp b/src/slic3r/GUI/GUI_ObjectManipulation.cpp
index 308b3f208d..0a2877d922 100644
--- a/src/slic3r/GUI/GUI_ObjectManipulation.cpp
+++ b/src/slic3r/GUI/GUI_ObjectManipulation.cpp
@@ -199,18 +199,17 @@ ObjectManipulation::ObjectManipulation(wxWindow* parent) :
     m_mirror_bitmap_off = ScalableBitmap(parent, "mirroring_off.png");
     m_mirror_bitmap_hidden = ScalableBitmap(parent, "mirroring_transparent.png");
 
-	for (const std::string axis : { "x", "y", "z" }) {
-        const std::string label = boost::algorithm::to_upper_copy(axis);
-        def.set_default_value(new ConfigOptionString{ "   " + label });
-        Option option = Option(def, axis + "_axis_legend");
-
-        unsigned int axis_idx = (axis[0] - 'x'); // 0, 1 or 2
+    static const char axes[] = { 'X', 'Y', 'Z' };
+    for (size_t axis_idx = 0; axis_idx < sizeof(axes); axis_idx++) {
+        const char label = axes[axis_idx];
+        def.set_default_value(new ConfigOptionString{ std::string("   ") + label });
+        Option option(def, std::string() + label + "_axis_legend");
 
         // We will add a button to toggle mirroring to each axis:
-        auto mirror_button = [this, mirror_btn_width, axis_idx, &label](wxWindow* parent) {
+        auto mirror_button = [this, mirror_btn_width, axis_idx, label](wxWindow* parent) {
             wxSize btn_size(em_unit(parent) * mirror_btn_width, em_unit(parent) * mirror_btn_width);
             auto btn = new ScalableButton(parent, wxID_ANY, "mirroring_off.png", wxEmptyString, btn_size, wxDefaultPosition, wxBU_EXACTFIT | wxNO_BORDER | wxTRANSPARENT_WINDOW);
-            btn->SetToolTip(wxString::Format(_(L("Toggle %s axis mirroring")), label));
+            btn->SetToolTip(wxString::Format(_(L("Toggle %c axis mirroring")), (int)label));
 
             m_mirror_buttons[axis_idx].first = btn;
             m_mirror_buttons[axis_idx].second = mbShown;
@@ -245,7 +244,8 @@ ObjectManipulation::ObjectManipulation(wxWindow* parent) :
                 canvas->do_mirror(L("Set Mirror"));
                 UpdateAndShow(true);
             });
-        return sizer;
+
+            return sizer;
         };
 
         option.side_widget = mirror_button;
diff --git a/src/slic3r/GUI/GUI_Preview.cpp b/src/slic3r/GUI/GUI_Preview.cpp
index 0ba447c1bc..36354ab240 100644
--- a/src/slic3r/GUI/GUI_Preview.cpp
+++ b/src/slic3r/GUI/GUI_Preview.cpp
@@ -63,7 +63,8 @@ bool View3D::init(wxWindow* parent, Bed3D& bed, Camera& camera, GLToolbar& view_
     m_canvas->set_config(config);
     m_canvas->enable_gizmos(true);
     m_canvas->enable_selection(true);
-    m_canvas->enable_toolbar(true);
+    m_canvas->enable_main_toolbar(true);
+    m_canvas->enable_undoredo_toolbar(true);
 
     wxBoxSizer* main_sizer = new wxBoxSizer(wxVERTICAL);
     main_sizer->Add(m_canvas_widget, 1, wxALL | wxEXPAND, 0);
diff --git a/src/slic3r/GUI/Gizmos/GLGizmosManager.cpp b/src/slic3r/GUI/Gizmos/GLGizmosManager.cpp
index 1509c1328b..dc819961f8 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmosManager.cpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmosManager.cpp
@@ -879,6 +879,60 @@ void GLGizmosManager::reset()
     m_gizmos.clear();
 }
 
+void GLGizmosManager::render_background(float left, float top, float right, float bottom, float border) const
+{
+    unsigned int tex_id = m_background_texture.texture.get_id();
+    float tex_width = (float)m_background_texture.texture.get_width();
+    float tex_height = (float)m_background_texture.texture.get_height();
+    if ((tex_id != 0) && (tex_width > 0) && (tex_height > 0))
+    {
+        float inv_tex_width = (tex_width != 0.0f) ? 1.0f / tex_width : 0.0f;
+        float inv_tex_height = (tex_height != 0.0f) ? 1.0f / tex_height : 0.0f;
+
+        float internal_left = left + border;
+        float internal_right = right - border;
+        float internal_top = top - border;
+        float internal_bottom = bottom + border;
+
+        float left_uv = 0.0f;
+        float right_uv = 1.0f;
+        float top_uv = 1.0f;
+        float bottom_uv = 0.0f;
+
+        float internal_left_uv = (float)m_background_texture.metadata.left * inv_tex_width;
+        float internal_right_uv = 1.0f - (float)m_background_texture.metadata.right * inv_tex_width;
+        float internal_top_uv = 1.0f - (float)m_background_texture.metadata.top * inv_tex_height;
+        float internal_bottom_uv = (float)m_background_texture.metadata.bottom * inv_tex_height;
+
+        // top-left corner
+        GLTexture::render_sub_texture(tex_id, left, internal_left, internal_top, top, { { internal_left_uv, internal_bottom_uv }, { internal_right_uv, internal_bottom_uv }, { internal_right_uv, internal_top_uv }, { internal_left_uv, internal_top_uv } });
+
+        // top edge
+        GLTexture::render_sub_texture(tex_id, internal_left, internal_right, internal_top, top, { { internal_left_uv, internal_top_uv }, { internal_right_uv, internal_top_uv }, { internal_right_uv, top_uv }, { internal_left_uv, top_uv } });
+
+        // top-right corner
+        GLTexture::render_sub_texture(tex_id, internal_right, right, internal_top, top, { { internal_right_uv, internal_top_uv }, { right_uv, internal_top_uv }, { right_uv, top_uv }, { internal_right_uv, top_uv } });
+
+        // center-left edge
+        GLTexture::render_sub_texture(tex_id, left, internal_left, internal_bottom, internal_top, { { internal_left_uv, internal_bottom_uv }, { internal_right_uv, internal_bottom_uv }, { internal_right_uv, internal_top_uv }, { internal_left_uv, internal_top_uv } });
+
+        // center
+        GLTexture::render_sub_texture(tex_id, internal_left, internal_right, internal_bottom, internal_top, { { internal_left_uv, internal_bottom_uv }, { internal_right_uv, internal_bottom_uv }, { internal_right_uv, internal_top_uv }, { internal_left_uv, internal_top_uv } });
+
+        // center-right edge
+        GLTexture::render_sub_texture(tex_id, internal_right, right, internal_bottom, internal_top, { { internal_right_uv, internal_bottom_uv }, { right_uv, internal_bottom_uv }, { right_uv, internal_top_uv }, { internal_right_uv, internal_top_uv } });
+
+        // bottom-left corner
+        GLTexture::render_sub_texture(tex_id, left, internal_left, bottom, internal_bottom, { { internal_left_uv, internal_bottom_uv }, { internal_right_uv, internal_bottom_uv }, { internal_right_uv, internal_top_uv }, { internal_left_uv, internal_top_uv } });
+
+        // bottom edge
+        GLTexture::render_sub_texture(tex_id, internal_left, internal_right, bottom, internal_bottom, { { internal_left_uv, bottom_uv }, { internal_right_uv, bottom_uv }, { internal_right_uv, internal_bottom_uv }, { internal_left_uv, internal_bottom_uv } });
+
+        // bottom-right corner
+        GLTexture::render_sub_texture(tex_id, internal_right, right, bottom, internal_bottom, { { internal_right_uv, bottom_uv }, { right_uv, bottom_uv }, { right_uv, internal_bottom_uv }, { internal_right_uv, internal_bottom_uv } });
+    }
+}
+
 void GLGizmosManager::do_render_overlay() const
 {
     if (m_gizmos.empty())
@@ -901,71 +955,7 @@ void GLGizmosManager::do_render_overlay() const
     float right = left + width * inv_zoom;
     float bottom = top - height * inv_zoom;
 
-    // renders background
-    unsigned int bg_tex_id = m_background_texture.texture.get_id();
-    float bg_tex_width = (float)m_background_texture.texture.get_width();
-    float bg_tex_height = (float)m_background_texture.texture.get_height();
-    if ((bg_tex_id != 0) && (bg_tex_width > 0) && (bg_tex_height > 0))
-    {
-        float inv_bg_tex_width = (bg_tex_width != 0.0f) ? 1.0f / bg_tex_width : 0.0f;
-        float inv_bg_tex_height = (bg_tex_height != 0.0f) ? 1.0f / bg_tex_height : 0.0f;
-
-        float bg_uv_left = 0.0f;
-        float bg_uv_right = 1.0f;
-        float bg_uv_top = 1.0f;
-        float bg_uv_bottom = 0.0f;
-
-        float bg_left = left;
-        float bg_right = right;
-        float bg_top = top;
-        float bg_bottom = bottom;
-        float bg_width = right - left;
-        float bg_height = top - bottom;
-        float bg_min_size = std::min(bg_width, bg_height);
-
-        float bg_uv_i_left = (float)m_background_texture.metadata.left * inv_bg_tex_width;
-        float bg_uv_i_right = 1.0f - (float)m_background_texture.metadata.right * inv_bg_tex_width;
-        float bg_uv_i_top = 1.0f - (float)m_background_texture.metadata.top * inv_bg_tex_height;
-        float bg_uv_i_bottom = (float)m_background_texture.metadata.bottom * inv_bg_tex_height;
-
-        float bg_i_left = bg_left + scaled_border;
-        float bg_i_right = bg_right - scaled_border;
-        float bg_i_top = bg_top - scaled_border;
-        float bg_i_bottom = bg_bottom + scaled_border;
-
-        bg_uv_left = bg_uv_i_left;
-        bg_i_left = bg_left;
-
-        if ((m_overlay_border > 0) && (bg_uv_top != bg_uv_i_top))
-        {
-            if (bg_uv_left != bg_uv_i_left)
-                GLTexture::render_sub_texture(bg_tex_id, bg_left, bg_i_left, bg_i_top, bg_top, { { bg_uv_left, bg_uv_i_top }, { bg_uv_i_left, bg_uv_i_top }, { bg_uv_i_left, bg_uv_top }, { bg_uv_left, bg_uv_top } });
-
-            GLTexture::render_sub_texture(bg_tex_id, bg_i_left, bg_i_right, bg_i_top, bg_top, { { bg_uv_i_left, bg_uv_i_top }, { bg_uv_i_right, bg_uv_i_top }, { bg_uv_i_right, bg_uv_top }, { bg_uv_i_left, bg_uv_top } });
-
-            if (bg_uv_right != bg_uv_i_right)
-                GLTexture::render_sub_texture(bg_tex_id, bg_i_right, bg_right, bg_i_top, bg_top, { { bg_uv_i_right, bg_uv_i_top }, { bg_uv_right, bg_uv_i_top }, { bg_uv_right, bg_uv_top }, { bg_uv_i_right, bg_uv_top } });
-        }
-
-        if ((m_overlay_border > 0) && (bg_uv_left != bg_uv_i_left))
-            GLTexture::render_sub_texture(bg_tex_id, bg_left, bg_i_left, bg_i_bottom, bg_i_top, { { bg_uv_left, bg_uv_i_bottom }, { bg_uv_i_left, bg_uv_i_bottom }, { bg_uv_i_left, bg_uv_i_top }, { bg_uv_left, bg_uv_i_top } });
-
-        GLTexture::render_sub_texture(bg_tex_id, bg_i_left, bg_i_right, bg_i_bottom, bg_i_top, { { bg_uv_i_left, bg_uv_i_bottom }, { bg_uv_i_right, bg_uv_i_bottom }, { bg_uv_i_right, bg_uv_i_top }, { bg_uv_i_left, bg_uv_i_top } });
-
-        if ((m_overlay_border > 0) && (bg_uv_right != bg_uv_i_right))
-            GLTexture::render_sub_texture(bg_tex_id, bg_i_right, bg_right, bg_i_bottom, bg_i_top, { { bg_uv_i_right, bg_uv_i_bottom }, { bg_uv_right, bg_uv_i_bottom }, { bg_uv_right, bg_uv_i_top }, { bg_uv_i_right, bg_uv_i_top } });
-
-        if ((m_overlay_border > 0) && (bg_uv_bottom != bg_uv_i_bottom))
-        {
-            if (bg_uv_left != bg_uv_i_left)
-                GLTexture::render_sub_texture(bg_tex_id, bg_left, bg_i_left, bg_bottom, bg_i_bottom, { { bg_uv_left, bg_uv_bottom }, { bg_uv_i_left, bg_uv_bottom }, { bg_uv_i_left, bg_uv_i_bottom }, { bg_uv_left, bg_uv_i_bottom } });
-
-            GLTexture::render_sub_texture(bg_tex_id, bg_i_left, bg_i_right, bg_bottom, bg_i_bottom, { { bg_uv_i_left, bg_uv_bottom }, { bg_uv_i_right, bg_uv_bottom }, { bg_uv_i_right, bg_uv_i_bottom }, { bg_uv_i_left, bg_uv_i_bottom } });
-
-            if (bg_uv_right != bg_uv_i_right)
-                GLTexture::render_sub_texture(bg_tex_id, bg_i_right, bg_right, bg_bottom, bg_i_bottom, { { bg_uv_i_right, bg_uv_bottom }, { bg_uv_right, bg_uv_bottom }, { bg_uv_right, bg_uv_i_bottom }, { bg_uv_i_right, bg_uv_i_bottom } });
-        }
-    }
+    render_background(left, top, right, bottom, scaled_border);
 
     top_x += scaled_border;
     top_y -= scaled_border;
diff --git a/src/slic3r/GUI/Gizmos/GLGizmosManager.hpp b/src/slic3r/GUI/Gizmos/GLGizmosManager.hpp
index 803613ec74..e1978e60dd 100644
--- a/src/slic3r/GUI/Gizmos/GLGizmosManager.hpp
+++ b/src/slic3r/GUI/Gizmos/GLGizmosManager.hpp
@@ -187,6 +187,7 @@ public:
 private:
     void reset();
 
+    void render_background(float left, float top, float right, float bottom, float border) const;
     void do_render_overlay() const;
 
     float get_total_overlay_height() const;
diff --git a/src/slic3r/GUI/Plater.cpp b/src/slic3r/GUI/Plater.cpp
index 0c65270fff..ed6677732b 100644
--- a/src/slic3r/GUI/Plater.cpp
+++ b/src/slic3r/GUI/Plater.cpp
@@ -3430,7 +3430,8 @@ void Plater::priv::init_view_toolbar()
     if (!view_toolbar.init(background_data))
         return;
 
-    view_toolbar.set_layout_orientation(GLToolbar::Layout::Bottom);
+    view_toolbar.set_horizontal_orientation(GLToolbar::Layout::HO_Left);
+    view_toolbar.set_vertical_orientation(GLToolbar::Layout::VO_Bottom);
     view_toolbar.set_border(5.0f);
     view_toolbar.set_gap_size(1.0f);
 
@@ -3594,6 +3595,13 @@ void Plater::priv::take_snapshot(const std::string& snapshot_name)
     unsigned int flags = 0;
     if (this->view3D->is_layers_editing_enabled())
     	flags |= UndoRedo::Snapshot::VARIABLE_LAYER_EDITING_ACTIVE;
+    //FIXME updating the Wipe tower config values at the ModelWipeTower from the Print config.
+    // This is a workaround until we refactor the Wipe Tower position / orientation to live solely inside the Model, not in the Print config.
+    if (this->printer_technology == ptFFF) {
+        const DynamicPrintConfig &config = wxGetApp().preset_bundle->prints.get_edited_preset().config;
+        model.wipe_tower.position = Vec2d(config.opt_float("wipe_tower_x"), config.opt_float("wipe_tower_y"));
+        model.wipe_tower.rotation = config.opt_float("wipe_tower_rotation_angle");
+    }
     this->undo_redo_stack.take_snapshot(snapshot_name, model, view3D->get_canvas3d()->get_selection(), view3D->get_canvas3d()->get_gizmos_manager(), this->printer_technology, flags);
     this->undo_redo_stack.release_least_recently_used();
     // Save the last active preset name of a particular printer technology.
@@ -3640,6 +3648,13 @@ void Plater::priv::undo_redo_to(std::vector<UndoRedo::Snapshot>::const_iterator
 	}
     // Save the last active preset name of a particular printer technology.
     ((this->printer_technology == ptFFF) ? m_last_fff_printer_profile_name : m_last_sla_printer_profile_name) = wxGetApp().preset_bundle->printers.get_selected_preset_name();
+    //FIXME updating the Wipe tower config values at the ModelWipeTower from the Print config.
+    // This is a workaround until we refactor the Wipe Tower position / orientation to live solely inside the Model, not in the Print config.
+    if (this->printer_technology == ptFFF) {
+        const DynamicPrintConfig &config = wxGetApp().preset_bundle->prints.get_edited_preset().config;
+                model.wipe_tower.position = Vec2d(config.opt_float("wipe_tower_x"), config.opt_float("wipe_tower_y"));
+                model.wipe_tower.rotation = config.opt_float("wipe_tower_rotation_angle");
+    }
     // Flags made of Snapshot::Flags enum values.
     unsigned int new_flags = it_snapshot->flags;
 	unsigned int top_snapshot_flags = 0;
@@ -3647,8 +3662,8 @@ void Plater::priv::undo_redo_to(std::vector<UndoRedo::Snapshot>::const_iterator
     	top_snapshot_flags |= UndoRedo::Snapshot::VARIABLE_LAYER_EDITING_ACTIVE;
 	bool   		 new_variable_layer_editing_active = (new_flags & UndoRedo::Snapshot::VARIABLE_LAYER_EDITING_ACTIVE) != 0;
 	// Disable layer editing before the Undo / Redo jump.
-    if (! new_variable_layer_editing_active && view3D->is_layers_editing_enabled())
-    	view3D->enable_layers_editing(false);
+    if (!new_variable_layer_editing_active && view3D->is_layers_editing_enabled())
+        view3D->get_canvas3d()->force_main_toolbar_left_action(view3D->get_canvas3d()->get_main_toolbar_item_id("layersediting"));
     // Do the jump in time.
     if (it_snapshot->timestamp < this->undo_redo_stack.active_snapshot_time() ?
 		this->undo_redo_stack.undo(model, this->view3D->get_canvas3d()->get_selection(), this->view3D->get_canvas3d()->get_gizmos_manager(), this->printer_technology, top_snapshot_flags, it_snapshot->timestamp) :
@@ -3662,11 +3677,27 @@ void Plater::priv::undo_redo_to(std::vector<UndoRedo::Snapshot>::const_iterator
         	// This also switches the printer technology based on the printer technology of the active printer profile.
         	wxGetApp().load_current_presets();
         }
-		this->update_after_undo_redo(temp_snapshot_was_taken);
+        //FIXME updating the Print config from the Wipe tower config values at the ModelWipeTower.
+        // This is a workaround until we refactor the Wipe Tower position / orientation to live solely inside the Model, not in the Print config.
+        if (this->printer_technology == ptFFF) {
+            const DynamicPrintConfig &current_config = wxGetApp().preset_bundle->prints.get_edited_preset().config;
+            Vec2d 					  current_position(current_config.opt_float("wipe_tower_x"), current_config.opt_float("wipe_tower_y"));
+            double 					  current_rotation = current_config.opt_float("wipe_tower_rotation_angle");
+            if (current_position != model.wipe_tower.position || current_rotation != model.wipe_tower.rotation) {
+                DynamicPrintConfig new_config;
+                new_config.set_key_value("wipe_tower_x", new ConfigOptionFloat(model.wipe_tower.position.x()));
+                new_config.set_key_value("wipe_tower_y", new ConfigOptionFloat(model.wipe_tower.position.y()));
+                new_config.set_key_value("wipe_tower_rotation_angle", new ConfigOptionFloat(model.wipe_tower.rotation));
+                Tab *tab_print = wxGetApp().get_tab(Preset::TYPE_PRINT);
+                tab_print->load_config(new_config);
+                tab_print->update_dirty();
+            }
+        }
+        this->update_after_undo_redo(temp_snapshot_was_taken);
 		// Enable layer editing after the Undo / Redo jump.
 		if (! view3D->is_layers_editing_enabled() && this->layers_height_allowed() && new_variable_layer_editing_active)
-			view3D->enable_layers_editing(true);
-	}
+            view3D->get_canvas3d()->force_main_toolbar_left_action(view3D->get_canvas3d()->get_main_toolbar_item_id("layersediting"));
+    }
 }
 
 void Plater::priv::update_after_undo_redo(bool /* temp_snapshot_was_taken */)
@@ -4278,6 +4309,19 @@ bool Plater::undo_redo_string_getter(const bool is_undo, int idx, const char** o
     return false;
 }
 
+void Plater::undo_redo_topmost_string_getter(const bool is_undo, std::string& out_text)
+{
+    const std::vector<UndoRedo::Snapshot>& ss_stack = p->undo_redo_stack.snapshots();
+    const int idx_in_ss_stack = p->get_active_snapshot_index() + (is_undo ? -1 : 0);
+
+    if (0 < idx_in_ss_stack && idx_in_ss_stack < ss_stack.size() - 1) {
+        out_text = ss_stack[idx_in_ss_stack].name;
+        return;
+    }
+
+    out_text = L("");
+}
+
 void Plater::on_extruders_change(int num_extruders)
 {
     auto& choices = sidebar().combos_filament();
diff --git a/src/slic3r/GUI/Plater.hpp b/src/slic3r/GUI/Plater.hpp
index d7e91f516c..e0737c6b9f 100644
--- a/src/slic3r/GUI/Plater.hpp
+++ b/src/slic3r/GUI/Plater.hpp
@@ -196,6 +196,7 @@ public:
     void undo_to(int selection);
     void redo_to(int selection);
     bool undo_redo_string_getter(const bool is_undo, int idx, const char** out_text);
+    void undo_redo_topmost_string_getter(const bool is_undo, std::string& out_text);
     const Slic3r::UndoRedo::Stack& undo_redo_stack() const;
 
     void on_extruders_change(int extruders_count);
diff --git a/src/slic3r/Utils/UndoRedo.cpp b/src/slic3r/Utils/UndoRedo.cpp
index 2605bd2a74..a8f9cc134a 100644
--- a/src/slic3r/Utils/UndoRedo.cpp
+++ b/src/slic3r/Utils/UndoRedo.cpp
@@ -514,11 +514,11 @@ public:
 	const Selection& 				selection_deserialized() const { return m_selection; }
 
 //protected:
-	template<typename T, typename T_AS> ObjectID save_mutable_object(const T &object);
+	template<typename T> ObjectID save_mutable_object(const T &object);
 	template<typename T> ObjectID save_immutable_object(std::shared_ptr<const T> &object, bool optional);
 	template<typename T> T* load_mutable_object(const Slic3r::ObjectID id);
 	template<typename T> std::shared_ptr<const T> load_immutable_object(const Slic3r::ObjectID id, bool optional);
-	template<typename T, typename T_AS> void load_mutable_object(const Slic3r::ObjectID id, T &target);
+	template<typename T> void load_mutable_object(const Slic3r::ObjectID id, T &target);
 
 #ifdef SLIC3R_UNDOREDO_DEBUG
 	std::string format() const {
@@ -601,7 +601,6 @@ class ModelObject;
 class ModelVolume;
 class ModelInstance;
 class ModelMaterial;
-class ModelConfig;
 class DynamicPrintConfig;
 class TriangleMesh;
 
@@ -616,14 +615,13 @@ namespace cereal
 	template <class Archive> struct specialize<Archive, Slic3r::ModelVolume*, cereal::specialization::non_member_load_save> {};
 	template <class Archive> struct specialize<Archive, Slic3r::ModelInstance*, cereal::specialization::non_member_load_save> {};
 	template <class Archive> struct specialize<Archive, Slic3r::ModelMaterial*, cereal::specialization::non_member_load_save> {};
-	template <class Archive> struct specialize<Archive, Slic3r::ModelConfig, cereal::specialization::non_member_load_save> {};
 	template <class Archive> struct specialize<Archive, std::shared_ptr<Slic3r::TriangleMesh>, cereal::specialization::non_member_load_save> {};
 
 	// Store ObjectBase derived class onto the Undo / Redo stack as a separate object,
 	// store just the ObjectID to this stream.
 	template <class T> void save(BinaryOutputArchive& ar, T* const& ptr)
 	{
-		ar(cereal::get_user_data<Slic3r::UndoRedo::StackImpl>(ar).save_mutable_object<T, T>(*ptr));
+		ar(cereal::get_user_data<Slic3r::UndoRedo::StackImpl>(ar).save_mutable_object<T>(*ptr));
 	}
 
 	// Load ObjectBase derived class from the Undo / Redo stack as a separate object
@@ -655,19 +653,18 @@ namespace cereal
 
 	// Store ObjectBase derived class onto the Undo / Redo stack as a separate object,
 	// store just the ObjectID to this stream.
-	void save(BinaryOutputArchive& ar, const Slic3r::ModelConfig &cfg)
+	template<class T> void save_by_value(BinaryOutputArchive& ar, const T &cfg)
 	{
-		ar(cereal::get_user_data<Slic3r::UndoRedo::StackImpl>(ar).save_mutable_object<Slic3r::ModelConfig, Slic3r::DynamicPrintConfig>(cfg));
+		ar(cereal::get_user_data<Slic3r::UndoRedo::StackImpl>(ar).save_mutable_object<T>(cfg));
 	}
-
 	// Load ObjectBase derived class from the Undo / Redo stack as a separate object
 	// based on the ObjectID loaded from this stream.
-	void load(BinaryInputArchive& ar, Slic3r::ModelConfig &cfg)
+	template<class T> void load_by_value(BinaryInputArchive& ar, T &cfg)
 	{
 		Slic3r::UndoRedo::StackImpl& stack = cereal::get_user_data<Slic3r::UndoRedo::StackImpl>(ar);
 		size_t id;
 		ar(id);
-		stack.load_mutable_object<Slic3r::ModelConfig, Slic3r::DynamicPrintConfig>(Slic3r::ObjectID(id), cfg);
+		stack.load_mutable_object<T>(Slic3r::ObjectID(id), cfg);
 	}
 
 	// Store ObjectBase derived class onto the Undo / Redo stack as a separate object,
@@ -723,7 +720,7 @@ template<typename T> std::shared_ptr<const T>& 	ImmutableObjectHistory<T>::share
 	return m_shared_object;
 }
 
-template<typename T, typename T_AS> ObjectID StackImpl::save_mutable_object(const T &object)
+template<typename T> ObjectID StackImpl::save_mutable_object(const T &object)
 {
 	// First find or allocate a history stack for the ObjectID of this object instance.
 	auto it_object_history = m_objects.find(object.id());
@@ -734,7 +731,7 @@ template<typename T, typename T_AS> ObjectID StackImpl::save_mutable_object(cons
 	std::ostringstream oss;
 	{
 		Slic3r::UndoRedo::OutputArchive archive(*this, oss);
-		archive(static_cast<const T_AS&>(object));
+		archive(object);
 	}
 	object_history->save(m_active_snapshot_time, m_current_time, oss.str());
 	return object.id();
@@ -758,7 +755,7 @@ template<typename T> ObjectID StackImpl::save_immutable_object(std::shared_ptr<c
 template<typename T> T* StackImpl::load_mutable_object(const Slic3r::ObjectID id)
 {
 	T *target = new T();
-	this->load_mutable_object<T, T>(id, *target);
+	this->load_mutable_object<T>(id, *target);
 	return target;
 }
 
@@ -775,7 +772,7 @@ template<typename T> std::shared_ptr<const T> StackImpl::load_immutable_object(c
 	return object_history->shared_ptr(*this);
 }
 
-template<typename T, typename T_AS> void StackImpl::load_mutable_object(const Slic3r::ObjectID id, T &target)
+template<typename T> void StackImpl::load_mutable_object(const Slic3r::ObjectID id, T &target)
 {
 	// First find a history stack for the ObjectID of this object instance.
 	auto it_object_history = m_objects.find(id);
@@ -785,7 +782,7 @@ template<typename T, typename T_AS> void StackImpl::load_mutable_object(const Sl
 	std::istringstream iss(object_history->load(m_active_snapshot_time));
 	Slic3r::UndoRedo::InputArchive archive(*this, iss);
 	target.m_id = id;
-	archive(static_cast<T_AS&>(target));
+	archive(target);
 }
 
 // Store the current application state onto the Undo / Redo stack, remove all snapshots after m_active_snapshot_time.
@@ -800,14 +797,14 @@ void StackImpl::take_snapshot(const std::string& snapshot_name, const Slic3r::Mo
 		m_snapshots.erase(it, m_snapshots.end());
 	}
 	// Take new snapshots.
-	this->save_mutable_object<Slic3r::Model, Slic3r::Model>(model);
+	this->save_mutable_object<Slic3r::Model>(model);
 	m_selection.volumes_and_instances.clear();
 	m_selection.volumes_and_instances.reserve(selection.get_volume_idxs().size());
 	m_selection.mode = selection.get_mode();
 	for (unsigned int volume_idx : selection.get_volume_idxs())
 		m_selection.volumes_and_instances.emplace_back(selection.get_volume(volume_idx)->geometry_id);
-	this->save_mutable_object<Selection, Selection>(m_selection);
-    this->save_mutable_object<Slic3r::GUI::GLGizmosManager, Slic3r::GUI::GLGizmosManager>(gizmos);
+	this->save_mutable_object<Selection>(m_selection);
+    this->save_mutable_object<Slic3r::GUI::GLGizmosManager>(gizmos);
     // Save the snapshot info.
 	m_snapshots.emplace_back(snapshot_name, m_current_time ++, model.id().id, printer_technology, flags);
 	m_active_snapshot_time = m_current_time;
@@ -833,12 +830,12 @@ void StackImpl::load_snapshot(size_t timestamp, Slic3r::Model& model, Slic3r::GU
 	m_active_snapshot_time = timestamp;
 	model.clear_objects();
 	model.clear_materials();
-	this->load_mutable_object<Slic3r::Model, Slic3r::Model>(ObjectID(it_snapshot->model_id), model);
+	this->load_mutable_object<Slic3r::Model>(ObjectID(it_snapshot->model_id), model);
 	model.update_links_bottom_up_recursive();
 	m_selection.volumes_and_instances.clear();
-	this->load_mutable_object<Selection, Selection>(m_selection.id(), m_selection);
+	this->load_mutable_object<Selection>(m_selection.id(), m_selection);
     gizmos.reset_all_states();
-    this->load_mutable_object<Slic3r::GUI::GLGizmosManager, Slic3r::GUI::GLGizmosManager>(gizmos.id(), gizmos);
+    this->load_mutable_object<Slic3r::GUI::GLGizmosManager>(gizmos.id(), gizmos);
     // Sort the volumes so that we may use binary search.
 	std::sort(m_selection.volumes_and_instances.begin(), m_selection.volumes_and_instances.end());
 	this->m_active_snapshot_time = timestamp;