From d6370a16fafc1efc6b5c19d2341e3ee3697abe68 Mon Sep 17 00:00:00 2001
From: YuSanka <yusanka@gmail.com>
Date: Mon, 9 Aug 2021 17:25:20 +0200
Subject: [PATCH] DoubleSlider: Fix for #6756 - Cannot Color Change (M600) at
 height when MMU Painting  + Fixed update for the ruler when "No sparce layer"
 option is enabled

---
 src/slic3r/GUI/DoubleSlider.cpp | 11 +++++++----
 src/slic3r/GUI/GUI_Preview.cpp  | 10 +++++-----
 2 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/src/slic3r/GUI/DoubleSlider.cpp b/src/slic3r/GUI/DoubleSlider.cpp
index 9134d6988d..94d6a2c647 100644
--- a/src/slic3r/GUI/DoubleSlider.cpp
+++ b/src/slic3r/GUI/DoubleSlider.cpp
@@ -384,7 +384,7 @@ void Control::SetTicksValues(const Info& custom_gcode_per_print_z)
         // Switch to the "Feature type"/"Tool" from the very beginning of a new object slicing after deleting of the old one
         post_ticks_changed_event();
 
-    if (custom_gcode_per_print_z.mode)
+    if (custom_gcode_per_print_z.mode && !custom_gcode_per_print_z.gcodes.empty())
         m_ticks.mode = custom_gcode_per_print_z.mode;
 
     Refresh();
@@ -439,7 +439,7 @@ void Control::SetModeAndOnlyExtruder(const bool is_one_extruder_printed_model, c
     m_mode = !is_one_extruder_printed_model ? MultiExtruder :
              only_extruder < 0              ? SingleExtruder :
                                               MultiAsSingle;
-    if (!m_ticks.mode)
+    if (!m_ticks.mode || (m_ticks.empty() && m_ticks.mode != m_mode))
         m_ticks.mode = m_mode;
     m_only_extruder = only_extruder;
 
@@ -546,7 +546,8 @@ bool Control::is_wipe_tower_layer(int tick) const
         return false;
     if (tick == 0 || (tick == (int)m_values.size() - 1 && m_values[tick] > m_values[tick - 1]))
         return false;
-    if (m_values[tick - 1] == m_values[tick + 1] && m_values[tick] < m_values[tick + 1])
+    if ((m_values[tick - 1] == m_values[tick + 1] && m_values[tick] < m_values[tick + 1]) ||
+        (tick > 0 && m_values[tick] < m_values[tick - 1]) ) // if there is just one wiping on the layer 
         return true;
 
     return false;
@@ -1078,7 +1079,9 @@ void Control::draw_ruler(wxDC& dc)
 {
     if (m_values.empty())
         return;
-    m_ruler.update(this->GetParent(), m_values, get_scroll_step());
+    // When "No sparce layer" is enabled, use m_layers_values for ruler update. 
+    // Because of m_values has duplicate values in this case.
+    m_ruler.update(this->GetParent(), m_layers_values.empty() ? m_values : m_layers_values, get_scroll_step());
 
     int height, width;
     get_size(&width, &height);
diff --git a/src/slic3r/GUI/GUI_Preview.cpp b/src/slic3r/GUI/GUI_Preview.cpp
index d17a277d8e..d87c23d81e 100644
--- a/src/slic3r/GUI/GUI_Preview.cpp
+++ b/src/slic3r/GUI/GUI_Preview.cpp
@@ -788,11 +788,11 @@ void Preview::update_layers_slider_mode()
                         object->config.option("extruder")->getInt() != extruder)
                         return false;
 
-                    if (object->volumes.size() > 1)
-                        for (ModelVolume* volume : object->volumes)
-                            if (volume->config.has("extruder") &&
-                                volume->config.option("extruder")->getInt() != extruder)
-                                return false;
+                    for (ModelVolume* volume : object->volumes)
+                        if (volume->config.has("extruder") &&
+                            volume->config.option("extruder")->getInt() != extruder ||
+                            !volume->mmu_segmentation_facets.empty())
+                            return false;
 
                     for (const auto& range : object->layer_config_ranges)
                         if (range.second.has("extruder") &&