diff --git a/src/slic3r/GUI/GUI_ObjectList.cpp b/src/slic3r/GUI/GUI_ObjectList.cpp
index 14773b593b..5a20756cef 100644
--- a/src/slic3r/GUI/GUI_ObjectList.cpp
+++ b/src/slic3r/GUI/GUI_ObjectList.cpp
@@ -283,7 +283,7 @@ void ObjectList::show_context_menu()
     const auto item = GetSelection();
     if (item)
     {
-        if (m_objects_model->IsSettingsItem(item))
+        if (!(m_objects_model->GetItemType(item) & (itObject | itVolume)))
             return;
         const auto menu = m_objects_model->GetParent(item) == wxDataViewItem(0) ?
             create_add_part_popupmenu() :
@@ -672,7 +672,7 @@ void ObjectList::load_subobject(bool is_modifier /*= false*/, bool is_lambda/* =
     parts_changed(obj_idx);
 
     for (int i = 0; i < part_names.size(); ++i) {
-        const wxDataViewItem sel_item = m_objects_model->AddChild(item, part_names.Item(i),
+        const wxDataViewItem sel_item = m_objects_model->AddVolumeChild(item, part_names.Item(i),
             is_modifier ? m_bmp_modifiermesh : m_bmp_solidmesh);
 
         if (i == part_names.size() - 1)
@@ -822,7 +822,7 @@ void ObjectList::load_lambda(const std::string& type_name)
     m_parts_changed = true;
     parts_changed(m_selected_object_id);
 
-    select_item(m_objects_model->AddChild(GetSelection(),
+    select_item(m_objects_model->AddVolumeChild(GetSelection(),
         name, m_bmp_modifiermesh));
 #ifndef __WXOSX__ //#ifdef __WXMSW__ // #ys_FIXME
     selection_changed();
@@ -896,14 +896,19 @@ bool ObjectList::del_subobject_from_object(const int obj_idx, const int idx, con
             if (vol->is_model_part())
                 ++solid_cnt;
         if (volume->is_model_part() && solid_cnt == 1) {
-            Slic3r::GUI::show_error(nullptr, _(L("You can't delete the last solid part from this object.")));
+            Slic3r::GUI::show_error(nullptr, _(L("You can't delete the last solid part from object.")));
             return false;
         }
 
         (*m_objects)[obj_idx]->delete_volume(idx);
     }
-    else if (type == itInstance)
+    else if (type == itInstance) {
+        if ((*m_objects)[obj_idx]->instances.size() == 1) {
+            Slic3r::GUI::show_error(nullptr, _(L("You can't delete the last intance from object.")));
+            return false;
+        }
         (*m_objects)[obj_idx]->delete_instance(idx);
+    }
     else
         return false;
 
@@ -934,7 +939,7 @@ void ObjectList::split(const bool split_part)
         m_objects_model->DeleteChildren(parent);
 
         for (auto id = 0; id < model_object->volumes.size(); id++)
-            m_objects_model->AddChild(parent, model_object->volumes[id]->name,
+            m_objects_model->AddVolumeChild(parent, model_object->volumes[id]->name,
             model_object->volumes[id]->is_modifier() ? m_bmp_modifiermesh : m_bmp_solidmesh,
             model_object->volumes[id]->config.has("extruder") ?
             model_object->volumes[id]->config.option<ConfigOptionInt>("extruder")->value : 0,
@@ -944,7 +949,7 @@ void ObjectList::split(const bool split_part)
     }
     else {
         for (auto id = 0; id < model_object->volumes.size(); id++)
-            m_objects_model->AddChild(item, model_object->volumes[id]->name,
+            m_objects_model->AddVolumeChild(item, model_object->volumes[id]->name,
             m_bmp_solidmesh,
             model_object->volumes[id]->config.has("extruder") ?
             model_object->volumes[id]->config.option<ConfigOptionInt>("extruder")->value : 0,
@@ -1034,7 +1039,7 @@ void ObjectList::part_selection_changed()
                     m_config = &(*m_objects)[obj_idx]->volumes[volume_id]->config;
                 }
             }
-            else {
+            else if (m_objects_model->GetItemType(item) == itVolume){
                 og_name = _(L("Part manipulation"));
                 is_part = true;
                 const auto volume_id = m_objects_model->GetVolumeIdByItem(item);
@@ -1088,7 +1093,7 @@ void ObjectList::add_object_to_list(size_t obj_idx)
 
     if (model_object->volumes.size() > 1) {
         for (auto id = 0; id < model_object->volumes.size(); id++)
-            m_objects_model->AddChild(item,
+            m_objects_model->AddVolumeChild(item,
             model_object->volumes[id]->name,
             m_bmp_solidmesh,
             model_object->volumes[id]->config.option<ConfigOptionInt>("extruder")->value,
@@ -1128,6 +1133,16 @@ void ObjectList::delete_all_objects_from_list()
     part_selection_changed();
 }
 
+void ObjectList::increase_object_instances(const size_t obj_idx, const size_t num)
+{
+    select_item(m_objects_model->AddInstanceChild(m_objects_model->GetItemById(obj_idx), num));
+}
+
+void ObjectList::decrease_object_instances(const size_t obj_idx, const size_t num)
+{
+    select_item(m_objects_model->DeleteLastInstance(m_objects_model->GetItemById(obj_idx), num));
+}
+
 void ObjectList::set_object_count(int idx, int count)
 {
     m_objects_model->SetValue(wxString::Format("%d", count), idx, 1);
@@ -1231,15 +1246,21 @@ void ObjectList::update_selections_on_canvas()
             return;
         }
 
-        auto parent = m_objects_model->GetParent(item);
-        const int obj_idx = m_objects_model->GetIdByItem(parent);
-        const int vol_idx = m_objects_model->GetVolumeIdByItem(item);
-        selection.add_volume(obj_idx, vol_idx, as_single_selection);        
+        if (m_objects_model->GetItemType(item) == itVolume) {
+            const int obj_idx = m_objects_model->GetIdByItem(m_objects_model->GetParent(item));
+            const int vol_idx = m_objects_model->GetVolumeIdByItem(item);
+            selection.add_volume(obj_idx, vol_idx, as_single_selection);
+        }
+        else if (m_objects_model->GetItemType(item) == itInstance) {
+            const int obj_idx = m_objects_model->GetIdByItem(m_objects_model->GetTopParent(item));
+            const int inst_idx = m_objects_model->GetInstanceIdByItem(item);
+            selection.add_instance(obj_idx, inst_idx, as_single_selection);
+        }
     };
 
     if (sel_cnt == 1) {
         wxDataViewItem item = GetSelection();
-        if (m_objects_model->IsSettingsItem(item))
+        if (m_objects_model->GetItemType(item) & (itSettings|itInstanceRoot))
             add_to_selection(m_objects_model->GetParent(item), selection, true);
         else
             add_to_selection(item, selection, true);
diff --git a/src/slic3r/GUI/GUI_ObjectList.hpp b/src/slic3r/GUI/GUI_ObjectList.hpp
index 418e1e8779..2325734bd7 100644
--- a/src/slic3r/GUI/GUI_ObjectList.hpp
+++ b/src/slic3r/GUI/GUI_ObjectList.hpp
@@ -112,6 +112,10 @@ public:
     void delete_volume_from_list(const size_t obj_idx, const size_t vol_idx);
     // Delete all objects from the list
     void delete_all_objects_from_list();
+    // Increase instances count
+    void increase_object_instances(const size_t obj_idx, const size_t num);
+    // Decrease instances count
+    void decrease_object_instances(const size_t obj_idx, const size_t num);
     // Set count of object on c++ side
     void set_object_count(int idx, int count);
 
diff --git a/src/slic3r/GUI/MainFrame.hpp b/src/slic3r/GUI/MainFrame.hpp
index ed2646b697..f298dc034e 100644
--- a/src/slic3r/GUI/MainFrame.hpp
+++ b/src/slic3r/GUI/MainFrame.hpp
@@ -30,11 +30,11 @@ class Tab;
 
 enum QuickSlice
 {
-    qsUndef,
-    qsReslice,
-    qsSaveAs,
-    qsExportSVG,
-    qsExportPNG
+    qsUndef = 0,
+    qsReslice = 1,
+    qsSaveAs = 2,
+    qsExportSVG = 4,
+    qsExportPNG = 8
 };
 
 struct PresetTab {
diff --git a/src/slic3r/GUI/Plater.cpp b/src/slic3r/GUI/Plater.cpp
index 9f0cdc89b8..7ef58d8bbc 100644
--- a/src/slic3r/GUI/Plater.cpp
+++ b/src/slic3r/GUI/Plater.cpp
@@ -1747,6 +1747,7 @@ void Plater::increase(size_t num)
     }
 
     sidebar().obj_list()->set_object_count(*obj_idx, model_object->instances.size());
+    sidebar().obj_list()->increase_object_instances(*obj_idx, num);
 
     if (p->get_config("autocenter") == "1") {
         p->arrange();
@@ -1771,6 +1772,7 @@ void Plater::decrease(size_t num)
             p->print.get_object(*obj_idx)->delete_last_copy();
         }
         sidebar().obj_list()->set_object_count(*obj_idx, model_object->instances.size());
+        sidebar().obj_list()->decrease_object_instances(*obj_idx, num);
     } else {
         remove(*obj_idx);
     }
diff --git a/src/slic3r/GUI/wxExtensions.cpp b/src/slic3r/GUI/wxExtensions.cpp
index 4b57540c2e..cd5f339e0b 100644
--- a/src/slic3r/GUI/wxExtensions.cpp
+++ b/src/slic3r/GUI/wxExtensions.cpp
@@ -429,7 +429,7 @@ wxDataViewItem PrusaObjectDataViewModel::Add(const wxString &name, const int ins
 	return child;
 }
 
-wxDataViewItem PrusaObjectDataViewModel::AddChild(	const wxDataViewItem &parent_item,
+wxDataViewItem PrusaObjectDataViewModel::AddVolumeChild(const wxDataViewItem &parent_item,
 													const wxString &name,
                                                     const wxBitmap& icon,
                                                     const int extruder/* = 0*/,
@@ -440,8 +440,7 @@ wxDataViewItem PrusaObjectDataViewModel::AddChild(	const wxDataViewItem &parent_
 
     const wxString extruder_str = extruder == 0 ? "default" : wxString::Format("%d", extruder);
 
-    if (create_frst_child && (root->GetChildren().Count() == 0 || 
-                             (root->GetChildren().Count() == 1 && root->GetNthChild(0)->m_type == itSettings)))
+    if (create_frst_child && root->m_volumes_cnt == 0)
 	{
 		const auto icon_solid_mesh = wxIcon(Slic3r::GUI::from_u8(Slic3r::var("object.png")), wxBITMAP_TYPE_PNG);
 		const auto node = new PrusaObjectDataViewModelNode(root, root->m_name, icon_solid_mesh, extruder_str, 0);
@@ -449,16 +448,17 @@ wxDataViewItem PrusaObjectDataViewModel::AddChild(	const wxDataViewItem &parent_
 		// notify control
 		const wxDataViewItem child((void*)node);
 		ItemAdded(parent_item, child);
+
+        root->m_volumes_cnt++;
 	}
 
-    const auto volume_id =  root->GetChildCount() > 0 && root->GetNthChild(0)->m_type == itSettings ?
-                            root->GetChildCount() - 1 : root->GetChildCount();
-
-	const auto node = new PrusaObjectDataViewModelNode(root, name, icon, extruder_str, volume_id);
+    const auto node = new PrusaObjectDataViewModelNode(root, name, icon, extruder_str, root->m_volumes_cnt);
 	root->Append(node);
 	// notify control
 	const wxDataViewItem child((void*)node);
-	ItemAdded(parent_item, child);
+    ItemAdded(parent_item, child);
+    root->m_volumes_cnt++;
+
 	return child;
 }
 
@@ -467,7 +467,7 @@ wxDataViewItem PrusaObjectDataViewModel::AddSettingsChild(const wxDataViewItem &
     PrusaObjectDataViewModelNode *root = (PrusaObjectDataViewModelNode*)parent_item.GetID();
     if (!root) return wxDataViewItem(0);
 
-    const auto node = new PrusaObjectDataViewModelNode(root);
+    const auto node = new PrusaObjectDataViewModelNode(root, itSettings);
     root->Insert(node, 0);
     // notify control
     const wxDataViewItem child((void*)node);
@@ -475,6 +475,55 @@ wxDataViewItem PrusaObjectDataViewModel::AddSettingsChild(const wxDataViewItem &
     return child;
 }
 
+int get_istances_root_idx(PrusaObjectDataViewModelNode *parent_node)
+{
+    int inst_root_id = -1;
+    int stop_search_i = parent_node->GetChildCount();
+    if (stop_search_i > 2) stop_search_i = 2;
+    for (int i = 0; i < stop_search_i; ++i)
+        if (parent_node->GetNthChild(i)->m_type & itInstanceRoot) {
+            inst_root_id = i;
+            break;
+        }
+    return inst_root_id;
+}
+
+wxDataViewItem PrusaObjectDataViewModel::AddInstanceChild(const wxDataViewItem &parent_item, size_t num)
+{
+    PrusaObjectDataViewModelNode *parent_node = (PrusaObjectDataViewModelNode*)parent_item.GetID();
+    if (!parent_node) return wxDataViewItem(0);
+
+    // Check and create/get instances root node
+    const int inst_root_id = get_istances_root_idx(parent_node);
+
+    PrusaObjectDataViewModelNode *inst_root_node = inst_root_id < 0 ? 
+                                                   new PrusaObjectDataViewModelNode(parent_node, itInstanceRoot) :
+                                                   parent_node->GetNthChild(inst_root_id);
+    const wxDataViewItem inst_root_item((void*)inst_root_node);
+
+    if (inst_root_id < 0) {
+        const unsigned insert_pos = parent_node->GetChildCount() == 0 || parent_node->GetNthChild(0)->m_type != itSettings ? 0 : 1;
+        parent_node->Insert(inst_root_node, insert_pos);
+        // notify control
+        ItemAdded(parent_item, inst_root_item);
+        num++;
+    }
+
+    // Add instance nodes
+    PrusaObjectDataViewModelNode *instance_node = nullptr;    
+    size_t counter = 0;
+    while (counter < num){
+        instance_node = new PrusaObjectDataViewModelNode(inst_root_node, itInstance);
+        inst_root_node->Append(instance_node);
+        // notify control
+        const wxDataViewItem instance_item((void*)instance_node);
+        ItemAdded(inst_root_item, instance_item);
+        ++counter;
+    }
+
+    return wxDataViewItem((void*)instance_node);
+}
+
 wxDataViewItem PrusaObjectDataViewModel::Delete(const wxDataViewItem &item)
 {
 	auto ret_item = wxDataViewItem(0);
@@ -505,6 +554,30 @@ wxDataViewItem PrusaObjectDataViewModel::Delete(const wxDataViewItem &item)
 			if (cur_idx > idx)
 				children[i]->SetIdx(cur_idx-1);
 		}
+
+        // if there is last instance item, delete both of it and instance root item
+        if (node_parent->GetChildCount() == 1 && node_parent->GetNthChild(0)->m_type == itInstance)
+        {
+            delete node;
+            ItemDeleted(parent, item);
+
+            PrusaObjectDataViewModelNode *last_instance_node = node_parent->GetNthChild(0);
+            node_parent->GetChildren().Remove(last_instance_node);
+            delete last_instance_node;
+            ItemDeleted(parent, wxDataViewItem(last_instance_node));
+
+            PrusaObjectDataViewModelNode *obj_node = node_parent->GetParent();
+            obj_node->GetChildren().Remove(node_parent);
+            delete node_parent;
+            ret_item = wxDataViewItem(obj_node);
+            ItemDeleted(ret_item, wxDataViewItem(node_parent));
+
+#ifndef __WXGTK__
+            if (obj_node->GetChildCount() == 0)
+                obj_node->m_container = false;
+#endif //__WXGTK__
+            return ret_item;
+        }
 	}
 	else
 	{
@@ -534,6 +607,54 @@ wxDataViewItem PrusaObjectDataViewModel::Delete(const wxDataViewItem &item)
 	return ret_item;
 }
 
+wxDataViewItem PrusaObjectDataViewModel::DeleteLastInstance(const wxDataViewItem &parent_item, size_t num)
+{
+    auto ret_item = wxDataViewItem(0);
+    PrusaObjectDataViewModelNode *parent_node = (PrusaObjectDataViewModelNode*)parent_item.GetID();
+    if (!parent_node) return ret_item;
+
+    const int inst_root_id = get_istances_root_idx(parent_node);
+    if (inst_root_id < 0) return ret_item;
+
+    wxDataViewItemArray items;
+    PrusaObjectDataViewModelNode *inst_root_node = parent_node->GetNthChild(inst_root_id);
+    const wxDataViewItem inst_root_item((void*)inst_root_node);
+
+    const int inst_cnt = inst_root_node->GetChildCount();
+    const bool delete_inst_root_item = inst_cnt - num < 2 ? true : false;
+
+    int stop = delete_inst_root_item ? 0 : inst_cnt - num;
+    for (int i = inst_cnt - 1; i >= stop;--i) {
+        PrusaObjectDataViewModelNode *last_instance_node = inst_root_node->GetNthChild(i);
+        inst_root_node->GetChildren().Remove(last_instance_node);
+        delete last_instance_node;
+        ItemDeleted(inst_root_item, wxDataViewItem(last_instance_node));
+    }
+
+//     for (int i = delete_inst_root_item ? 0 : inst_cnt - num; i < inst_cnt; ++i)
+//         items.Add(wxDataViewItem(inst_root_node->GetNthChild(i)));
+// 
+//     if (delete_inst_root_item)
+//         inst_root_node->GetChildren().RemoveAt(0, inst_cnt);
+//     else {
+//         ret_item = wxDataViewItem(inst_root_node->GetNthChild(inst_cnt - num - 1));
+//         inst_root_node->GetChildren().RemoveAt(inst_cnt - num, num);
+//     }
+
+//     ItemsDeleted(inst_root_item, items);
+    if (delete_inst_root_item) {
+        ret_item = parent_item;
+        parent_node->GetChildren().Remove(inst_root_node);
+        ItemDeleted(parent_item, inst_root_item);
+#ifndef __WXGTK__
+        if (parent_node->GetChildCount() == 0)
+            parent_node->m_container = false;
+#endif //__WXGTK__
+    }
+
+    return ret_item;
+}
+
 void PrusaObjectDataViewModel::DeleteAll()
 {
 	while (!m_objects.empty())
@@ -620,36 +741,49 @@ int PrusaObjectDataViewModel::GetIdByItem(const wxDataViewItem& item)
 	return it - m_objects.begin();
 }
 
-int PrusaObjectDataViewModel::GetVolumeIdByItem(const wxDataViewItem& item)
+int PrusaObjectDataViewModel::GetIdByItemAndType(const wxDataViewItem& item, const ItemType type) const
 {
 	wxASSERT(item.IsOk());
 
 	PrusaObjectDataViewModelNode *node = (PrusaObjectDataViewModelNode*)item.GetID();
-	if (!node || node->m_type != itVolume)
+	if (!node || node->m_type != type)
 		return -1;
 	return node->GetIdx();
 }
 
+int PrusaObjectDataViewModel::GetVolumeIdByItem(const wxDataViewItem& item) const
+{
+    return GetIdByItemAndType(item, itVolume);
+}
+
+int PrusaObjectDataViewModel::GetInstanceIdByItem(const wxDataViewItem& item) const 
+{
+    return GetIdByItemAndType(item, itInstance);
+}
+
 void PrusaObjectDataViewModel::GetItemInfo(const wxDataViewItem& item, ItemType& type, int& obj_idx, int& idx)
 {
     wxASSERT(item.IsOk());
     type = itUndef;
 
     PrusaObjectDataViewModelNode *node = (PrusaObjectDataViewModelNode*)item.GetID();
-    if (!node) return;
+    if (!node || node->GetIdx() < 0 && node->GetType() != itObject) 
+        return;
 
-    type = node->GetType();
     idx = node->GetIdx();
+    type = node->GetType();
 
     PrusaObjectDataViewModelNode *parent_node = node->GetParent();
     if (!parent_node) return;
     if (type == itInstance)
         parent_node = node->GetParent()->GetParent();
-    if (!parent_node) return;
+    if (!parent_node || parent_node->m_type != itObject) { type = itUndef; return; }
 
     auto it = find(m_objects.begin(), m_objects.end(), parent_node);
     if (it != m_objects.end())
         obj_idx = it - m_objects.begin();
+    else
+        type = itUndef;
 }
 
 wxString PrusaObjectDataViewModel::GetName(const wxDataViewItem &item) const
@@ -819,12 +953,32 @@ wxDataViewItem PrusaObjectDataViewModel::GetParent(const wxDataViewItem &item) c
 	PrusaObjectDataViewModelNode *node = (PrusaObjectDataViewModelNode*)item.GetID();
 
 	// objects nodes has no parent too
-	if (find(m_objects.begin(), m_objects.end(),node) != m_objects.end())
+    if (node->m_type == itObject)
 		return wxDataViewItem(0);
 
 	return wxDataViewItem((void*)node->GetParent());
 }
 
+wxDataViewItem PrusaObjectDataViewModel::GetTopParent(const wxDataViewItem &item) const
+{
+	// the invisible root node has no parent
+	if (!item.IsOk())
+		return wxDataViewItem(0);
+
+	PrusaObjectDataViewModelNode *node = (PrusaObjectDataViewModelNode*)item.GetID();
+    if (node->m_type == itObject)
+        return item;
+
+    PrusaObjectDataViewModelNode *parent_node = node->GetParent();
+    while (parent_node->m_type != itObject)
+    {
+        node = parent_node;
+        parent_node = node->GetParent();
+    }
+
+    return wxDataViewItem((void*)parent_node);
+}
+
 bool PrusaObjectDataViewModel::IsContainer(const wxDataViewItem &item) const
 {
 	// the invisible root node can have children
diff --git a/src/slic3r/GUI/wxExtensions.hpp b/src/slic3r/GUI/wxExtensions.hpp
index f3c417426f..c1ff4074e2 100644
--- a/src/slic3r/GUI/wxExtensions.hpp
+++ b/src/slic3r/GUI/wxExtensions.hpp
@@ -195,12 +195,12 @@ DECLARE_VARIANT_OBJECT(PrusaDataViewBitmapText)
 // ----------------------------------------------------------------------------
 
 enum ItemType{
-    itUndef,
-    itObject,
-    itVolume,
-    itInstanceRoot,
-    itInstance,
-    itSettings
+    itUndef = 0,
+    itObject = 1,
+    itVolume = 2,
+    itInstanceRoot = 4,
+    itInstance = 8,
+    itSettings = 16
 };
 
 class PrusaObjectDataViewModelNode;
@@ -211,6 +211,7 @@ class PrusaObjectDataViewModelNode
 	PrusaObjectDataViewModelNode*	m_parent;
 	MyObjectTreeModelNodePtrArray   m_children;
     wxBitmap                        m_empty_bmp;
+    size_t                          m_volumes_cnt = 0;
     std::vector< std::string >      m_opt_categories;
 public:
 	PrusaObjectDataViewModelNode(const wxString &name, const int instances_count=1) {
@@ -248,7 +249,7 @@ public:
 		set_part_action_icon();
     }
 
-    PrusaObjectDataViewModelNode(   PrusaObjectDataViewModelNode* parent, const ItemType type = itSettings) :
+    PrusaObjectDataViewModelNode(   PrusaObjectDataViewModelNode* parent, const ItemType type) :
                                     m_parent(parent),
                                     m_copy(wxEmptyString),
                                     m_type(type),
@@ -261,8 +262,8 @@ public:
             m_name = "Instances";            
         }
         else if (type == itInstance) {
-            m_name = wxString::Format("Instances_%d", parent->GetChildCount() + 1);
             m_idx = parent->GetChildCount();
+            m_name = wxString::Format("Instance_%d", m_idx+1);
         }
 	}
 
@@ -370,7 +371,11 @@ public:
 
 	void SetIdx(const int& idx) {
 		m_idx = idx;
+        // update name if this node is instance
+        if (m_type == itInstance)
+            m_name = wxString::Format("Instance_%d", m_idx + 1);
 	}
+
 	int GetIdx() const {
 		return m_idx;
 	}
@@ -407,6 +412,8 @@ public:
 	void set_object_action_icon();
 	void set_part_action_icon();
     bool update_settings_digest(const std::vector<std::string>& categories);
+private:
+    friend class PrusaObjectDataViewModel;
 };
 
 // ----------------------------------------------------------------------------
@@ -422,19 +429,23 @@ public:
 
 	wxDataViewItem Add(const wxString &name);
 	wxDataViewItem Add(const wxString &name, const int instances_count);
-	wxDataViewItem AddChild(const wxDataViewItem &parent_item, 
+	wxDataViewItem AddVolumeChild(const wxDataViewItem &parent_item, 
 							const wxString &name, 
                             const wxBitmap& icon,
                             const int extruder = 0,
                             const bool create_frst_child = true);
 	wxDataViewItem AddSettingsChild(const wxDataViewItem &parent_item);
+    wxDataViewItem AddInstanceChild(const wxDataViewItem &parent_item, size_t num);
 	wxDataViewItem Delete(const wxDataViewItem &item);
+	wxDataViewItem DeleteLastInstance(const wxDataViewItem &parent_item, size_t num);
 	void DeleteAll();
     void DeleteChildren(wxDataViewItem& parent);
 	wxDataViewItem GetItemById(int obj_idx);
 	wxDataViewItem GetItemByVolumeId(int obj_idx, int volume_idx);
 	int GetIdByItem(const wxDataViewItem& item);
-	int GetVolumeIdByItem(const wxDataViewItem& item);
+    int GetIdByItemAndType(const wxDataViewItem& item, const ItemType type) const;
+    int GetVolumeIdByItem(const wxDataViewItem& item) const;
+    int GetInstanceIdByItem(const wxDataViewItem& item) const;
     void GetItemInfo(const wxDataViewItem& item, ItemType& type, int& obj_idx, int& idx);
     bool IsEmpty() { return m_objects.empty(); }
 
@@ -466,6 +477,8 @@ public:
 	virtual bool IsEnabled(const wxDataViewItem &item, unsigned int col) const override;
 
 	virtual wxDataViewItem GetParent(const wxDataViewItem &item) const override;
+    // get object item
+    wxDataViewItem GetTopParent(const wxDataViewItem &item) const;
 	virtual bool IsContainer(const wxDataViewItem &item) const override;
 	virtual unsigned int GetChildren(const wxDataViewItem &parent,
 		wxDataViewItemArray &array) const override;