diff --git a/cura/Machines/Models/MaterialsModel.py b/cura/Machines/Models/MaterialsModel.py
index 616903062e..5ef5845371 100644
--- a/cura/Machines/Models/MaterialsModel.py
+++ b/cura/Machines/Models/MaterialsModel.py
@@ -30,7 +30,7 @@ def getAvailableMaterials(extruder_position: Optional[int] = None):
     variant_name = None
     if extruder_stack.variant.getId() != "empty_variant":
         variant_name = extruder_stack.variant.getName()
-    diameter = extruder_stack.getProperty("material_diameter", "value")
+    diameter = extruder_stack.approximateMaterialDiameter
 
     # Fetch the available materials (ContainerNode) for the current active machine and extruder setup.
     result_dict = material_manager.getAvailableMaterials(machine_definition_id, variant_name, diameter)
diff --git a/cura/Settings/ExtruderManager.py b/cura/Settings/ExtruderManager.py
index 178cf31e3f..fe1bb6a990 100755
--- a/cura/Settings/ExtruderManager.py
+++ b/cura/Settings/ExtruderManager.py
@@ -179,6 +179,7 @@ class ExtruderManager(QObject):
         self._selected_object_extruders = []
         self.selectedObjectExtrudersChanged.emit()
 
+    @pyqtSlot(result = QObject)
     def getActiveExtruderStack(self) -> Optional["ExtruderStack"]:
         global_container_stack = Application.getInstance().getGlobalContainerStack()
 
diff --git a/cura/Settings/ExtruderStack.py b/cura/Settings/ExtruderStack.py
index 870de62c98..2995aae795 100644
--- a/cura/Settings/ExtruderStack.py
+++ b/cura/Settings/ExtruderStack.py
@@ -3,6 +3,8 @@
 
 from typing import Any, TYPE_CHECKING, Optional
 
+from PyQt5.QtCore import pyqtProperty
+
 from UM.Decorators import override
 from UM.MimeTypeDatabase import MimeType, MimeTypeDatabase
 from UM.Settings.ContainerStack import ContainerStack
@@ -49,6 +51,33 @@ class ExtruderStack(CuraContainerStack):
     def getLoadingPriority(cls) -> int:
         return 3
 
+    ##  Return the filament diameter that the machine requires.
+    #
+    #   If the machine has no requirement for the diameter, -1 is returned.
+    #   \return The filament diameter for the printer
+    @property
+    def materialDiameter(self) -> float:
+        containers_to_check = [self.variant, self.definitionChanges, self.definition]
+
+        for container in containers_to_check:
+            if container is not None:
+                material_diameter = container.getProperty("material_diameter", "value")
+                if material_diameter is not None:
+                    return material_diameter
+        return -1
+
+    ##  Return the approximate filament diameter that the machine requires.
+    #
+    #   The approximate material diameter is the material diameter rounded to
+    #   the nearest millimetre.
+    #
+    #   If the machine has no requirement for the diameter, -1 is returned.
+    #
+    #   \return The approximate filament diameter for the printer
+    @pyqtProperty(float)
+    def approximateMaterialDiameter(self) -> float:
+        return round(float(self.materialDiameter))
+
     ##  Overridden from ContainerStack
     #
     #   It will perform a few extra checks when trying to get properties.
diff --git a/cura/Settings/GlobalStack.py b/cura/Settings/GlobalStack.py
index 6d18bf615b..ae1f1370ed 100755
--- a/cura/Settings/GlobalStack.py
+++ b/cura/Settings/GlobalStack.py
@@ -125,21 +125,6 @@ class GlobalStack(CuraContainerStack):
     def setNextStack(self, next_stack: ContainerStack) -> None:
         raise Exceptions.InvalidOperationError("Global stack cannot have a next stack!")
 
-    ##  Gets the approximate filament diameter that the machine requires.
-    #
-    #   The approximate material diameter is the material diameter rounded to
-    #   the nearest millimetre.
-    #
-    #   If the machine has no requirement for the diameter, -1 is returned.
-    #
-    #   \return The approximate filament diameter for the printer, as a string.
-    @pyqtProperty(str)
-    def approximateMaterialDiameter(self) -> str:
-        material_diameter = self.definition.getProperty("material_diameter", "value")
-        if material_diameter is None:
-            return "-1"
-        return str(round(float(material_diameter))) #Round, then convert back to string.
-
     # protected:
 
     # Determine whether or not we should try to get the "resolve" property instead of the
diff --git a/resources/qml/Preferences/MaterialView.qml b/resources/qml/Preferences/MaterialView.qml
index 3dc16c5a86..021fcc02e1 100644
--- a/resources/qml/Preferences/MaterialView.qml
+++ b/resources/qml/Preferences/MaterialView.qml
@@ -207,7 +207,7 @@ TabView
                         var old_diameter = Cura.ContainerManager.getContainerProperty(base.containerId, "material_diameter", "value").toString();
                         var old_approximate_diameter = Cura.ContainerManager.getContainerMetaDataEntry(base.containerId, "approximate_diameter");
                         var new_approximate_diameter = getApproximateDiameter(value);
-                        if (Cura.MachineManager.filterMaterialsByMachine && new_approximate_diameter != Cura.MachineManager.activeMachine.approximateMaterialDiameter)
+                        if (Cura.MachineManager.filterMaterialsByMachine && new_approximate_diameter != Cura.ExtruderManager.getActiveExtruderStack().approximateMaterialDiameter)
                         {
                             confirmDiameterChangeDialog.old_diameter_value = old_diameter;
                             confirmDiameterChangeDialog.new_diameter_value = value;