Only update ExtrudersModel when material changes

CURA-3780

cura/Settings/ExtrudersModel.py

@@ -116,10 +116,10 @@ class ExtrudersModel(UM.Qt.ListModel.ListModel):
                 active_extruder_stack.containersChanged.connect(self._onExtruderStackContainersChanged)
             self._active_extruder_stack = active_extruder_stack
 
-
     def _onExtruderStackContainersChanged(self, container):
-        # The ExtrudersModel needs to be updated when the material-name or -color changes, because the user identifies extruders by material-name
-        self._updateExtruders()
+        if container.getMetaDataEntry("type") == "material":
+            # The ExtrudersModel needs to be updated when the material-name or -color changes, because the user identifies extruders by material-name
+            self._updateExtruders()
 
     modelChanged = pyqtSignal()
 
@@ -141,7 +141,7 @@ class ExtrudersModel(UM.Qt.ListModel.ListModel):
         global_container_stack = Application.getInstance().getGlobalContainerStack()
         if global_container_stack:
             if self._add_global:
-                material = global_container_stack.findContainer({ "type": "material" })
+                material = global_container_stack.material
                 color = material.getMetaDataEntry("color_code", default = self.defaultColors[0]) if material else self.defaultColors[0]
                 item = {
                     "id": global_container_stack.getId(),
@@ -156,9 +156,6 @@ class ExtrudersModel(UM.Qt.ListModel.ListModel):
             machine_extruder_count = global_container_stack.getProperty("machine_extruder_count", "value")
             manager = ExtruderManager.getInstance()
             for extruder in manager.getMachineExtruders(global_container_stack.getId()):
-                extruder_name = extruder.getName()
-                material = extruder.findContainer({ "type": "material" })
-                variant = extruder.findContainer({"type": "variant"})
                 position = extruder.getMetaDataEntry("position", default = "0")  # Get the position
                 try:
                     position = int(position)
@@ -166,6 +163,9 @@ class ExtrudersModel(UM.Qt.ListModel.ListModel):
                     position = -1
                 if position >= machine_extruder_count:
                     continue
+                extruder_name = extruder.getName()
+                material = extruder.material
+                variant = extruder.variant
 
                 default_color = self.defaultColors[position] if position >= 0 and position < len(self.defaultColors) else self.defaultColors[0]
                 color = material.getMetaDataEntry("color_code", default = default_color) if material else default_color