diff --git a/cura/Settings/MachineManager.py b/cura/Settings/MachineManager.py
index 764ad8ed43..44b67b721c 100755
--- a/cura/Settings/MachineManager.py
+++ b/cura/Settings/MachineManager.py
@@ -1112,9 +1112,17 @@ class MachineManager(QObject):
     def _onRootMaterialChanged(self) -> None:
         self._current_root_material_id = {}
 
+        changed = False
+
         if self._global_container_stack:
             for position in self._global_container_stack.extruders:
-                self._current_root_material_id[position] = self._global_container_stack.extruders[position].material.getMetaDataEntry("base_file")
+                material_id = self._global_container_stack.extruders[position].material.getMetaDataEntry("base_file")
+                if position not in self._current_root_material_id or material_id != self._current_root_material_id[position]:
+                    changed = True
+                    self._current_root_material_id[position] = material_id
+
+        if changed:
+            self.activeMaterialChanged.emit()
 
     @pyqtProperty("QVariant", notify = rootMaterialChanged)
     def currentRootMaterialId(self) -> Dict[str, str]:
diff --git a/resources/qml/Preferences/Materials/MaterialsPage.qml b/resources/qml/Preferences/Materials/MaterialsPage.qml
index 92c20d575f..1ec1648c7b 100644
--- a/resources/qml/Preferences/Materials/MaterialsPage.qml
+++ b/resources/qml/Preferences/Materials/MaterialsPage.qml
@@ -49,6 +49,15 @@ Item
     // When loaded, try to select the active material in the tree
     Component.onCompleted: resetExpandedActiveMaterial()
 
+    Connections
+    {
+        target: Cura.MachineManager
+        onActiveMaterialChanged:
+        {
+            resetExpandedActiveMaterial()
+        }
+    }
+
     // Every time the selected item has changed, notify to the details panel
     onCurrentItemChanged:
     {
diff --git a/resources/qml/Preferences/Materials/MaterialsSlot.qml b/resources/qml/Preferences/Materials/MaterialsSlot.qml
index 5a44fb49cc..6df77714c2 100644
--- a/resources/qml/Preferences/Materials/MaterialsSlot.qml
+++ b/resources/qml/Preferences/Materials/MaterialsSlot.qml
@@ -51,7 +51,7 @@ Rectangle
         anchors.left: swatch.right
         anchors.verticalCenter: materialSlot.verticalCenter
         anchors.leftMargin: UM.Theme.getSize("narrow_margin").width
-        font.italic: Cura.MachineManager.currentRootMaterialId[Cura.ExtruderManager.activeExtruderIndex] == material.root_material_id
+        font.italic: material != null && Cura.MachineManager.currentRootMaterialId[Cura.ExtruderManager.activeExtruderIndex] == material.root_material_id
     }
     MouseArea
     {