diff --git a/src/libslic3r/GCode/GCodeProcessor.cpp b/src/libslic3r/GCode/GCodeProcessor.cpp
index 651808bb8..918d6d549 100644
--- a/src/libslic3r/GCode/GCodeProcessor.cpp
+++ b/src/libslic3r/GCode/GCodeProcessor.cpp
@@ -723,6 +723,12 @@ void GCodeProcessor::UsedFilaments::reset()
     support_volume_per_extruder.clear();
 }
 
+void GCodeProcessor::UsedFilaments::increase_support_caches(double extruded_volume)
+{
+    support_volume_cache += extruded_volume;
+    role_cache += extruded_volume;
+}
+
 void GCodeProcessor::UsedFilaments::increase_model_caches(double extruded_volume)
 {
     color_change_cache += extruded_volume;
@@ -768,6 +774,18 @@ void GCodeProcessor::UsedFilaments::process_wipe_tower_cache(GCodeProcessor* pro
     }
 }
 
+void GCodeProcessor::UsedFilaments::process_support_cache(GCodeProcessor* processor)
+{
+    size_t active_extruder_id = processor->m_extruder_id;
+    if (support_volume_cache != 0.0f){
+        if (support_volume_per_extruder.find(active_extruder_id) != support_volume_per_extruder.end())
+            support_volume_per_extruder[active_extruder_id] += support_volume_cache;
+        else
+            support_volume_per_extruder[active_extruder_id] = support_volume_cache;
+        support_volume_cache = 0.0f;
+    }
+}
+
 void GCodeProcessor::UsedFilaments::update_flush_per_filament(size_t extrude_id, float flush_volume)
 {
     if (flush_per_filament.find(extrude_id) != flush_per_filament.end())
diff --git a/src/libslic3r/GCode/GCodeProcessor.hpp b/src/libslic3r/GCode/GCodeProcessor.hpp
index 9a339244f..a0a6c4c68 100644
--- a/src/libslic3r/GCode/GCodeProcessor.hpp
+++ b/src/libslic3r/GCode/GCodeProcessor.hpp
@@ -511,27 +511,14 @@ namespace Slic3r {
 
             void reset();
 
-            void increase_support_caches(double extruded_volume){
-                support_volume_cache += extruded_volume;
-                role_cache += extruded_volume;
-            }
-
+            void increase_support_caches(double extruded_volume);
             void increase_model_caches(double extruded_volume);
             void increase_wipe_tower_caches(double extruded_volume);
 
             void process_color_change_cache();
             void process_model_cache(GCodeProcessor* processor);
             void process_wipe_tower_cache(GCodeProcessor* processor);
-            void process_support_cache(GCodeProcessor* processor){
-                size_t active_extruder_id = processor->m_extruder_id;
-                if (support_volume_cache != 0.0f) {
-                    if (support_volume_per_extruder.find(active_extruder_id) != support_volume_per_extruder.end())
-                        support_volume_per_extruder[active_extruder_id] += support_volume_cache;
-                    else
-                        support_volume_per_extruder[active_extruder_id] = support_volume_cache;
-                    support_volume_cache = 0.0f;
-                }
-            }
+            void process_support_cache(GCodeProcessor* processor);
 
             void update_flush_per_filament(size_t extrude_id, float flush_length);
             void process_role_cache(GCodeProcessor* processor);
diff --git a/src/slic3r/GUI/PartPlate.cpp b/src/slic3r/GUI/PartPlate.cpp
index dd60fdbc6..e4dbba07e 100644
--- a/src/slic3r/GUI/PartPlate.cpp
+++ b/src/slic3r/GUI/PartPlate.cpp
@@ -1636,11 +1636,19 @@ std::vector<int> PartPlate::get_used_extruders()
 	if (!result)
 		return used_extruders;
 
+	std::set<int> used_extruders_set;
 	PrintEstimatedStatistics& ps = result->print_statistics;
-	for (auto it = ps.volumes_per_extruder.begin(); it != ps.volumes_per_extruder.end(); it++) {
-		used_extruders.push_back(it->first + 1);
-	}
-	return used_extruders;
+	// model usage
+	for (const auto&item:ps.volumes_per_extruder)
+		used_extruders_set.emplace(item.first + 1);
+	// support usage
+	for (const auto&item:ps.support_volumes_per_extruder)
+		used_extruders_set.emplace(item.first + 1);
+	// wipe tower usage
+	for (const auto&item:ps.wipe_tower_volumes_per_extruder)
+		used_extruders_set.emplace(item.first + 1);
+
+	return std::vector(used_extruders_set.begin(), used_extruders_set.end());
 }
 
 Vec3d PartPlate::estimate_wipe_tower_size(const DynamicPrintConfig & config, const double w, const double wipe_volume, int plate_extruder_size, bool use_global_objects) const