diff --git a/cura/Settings/ExtrudersModel.py b/cura/Settings/ExtrudersModel.py
index d46a9cbae1..26943e61ca 100644
--- a/cura/Settings/ExtrudersModel.py
+++ b/cura/Settings/ExtrudersModel.py
@@ -70,7 +70,7 @@ class ExtrudersModel(UM.Qt.ListModel.ListModel):
         self._simple_names = False
 
         self._active_machine_extruders = [] # type: Iterable[ExtruderStack]
-        self._use_optional_extruder = False
+        self._add_optional_extruder = False
 
         #Listen to changes.
         Application.getInstance().globalContainerStackChanged.connect(self._extrudersChanged) #When the machine is swapped we must update the active machine extruders.
@@ -89,17 +89,17 @@ class ExtrudersModel(UM.Qt.ListModel.ListModel):
     def addGlobal(self):
         return self._add_global
 
-    useOptionalExtruderChanged = pyqtSignal()
+    addOptionalExtruderChanged = pyqtSignal()
 
-    def setUseOptionalExtruder(self, use_optional_extruder):
-        if use_optional_extruder != self._use_optional_extruder:
-            self._use_optional_extruder = use_optional_extruder
-            self.useOptionalExtruderChanged.emit()
+    def setAddOptionalExtruder(self, add_optional_extruder):
+        if add_optional_extruder != self._add_optional_extruder:
+            self._add_optional_extruder = add_optional_extruder
+            self.addOptionalExtruderChanged.emit()
             self._updateExtruders()
 
-    @pyqtProperty(bool, fset = setUseOptionalExtruder, notify = useOptionalExtruderChanged)
-    def useOptionalExtruder(self):
-        return self._use_optional_extruder
+    @pyqtProperty(bool, fset = setAddOptionalExtruder, notify = addOptionalExtruderChanged)
+    def addOptionalExtruder(self):
+        return self._add_optional_extruder
 
     ##  Set the simpleNames property.
     def setSimpleNames(self, simple_names):
@@ -212,9 +212,9 @@ class ExtrudersModel(UM.Qt.ListModel.ListModel):
             items.sort(key = lambda i: i["index"])
             # We need optional extruder to be last, so add it after we do sorting.
             # This way we can simply intrepret the -1 of the index as the last item (which it now always is)
-            if self._use_optional_extruder:
+            if self._add_optional_extruder:
                 item = {
-                    "id": "zomg",
+                    "id": "",
                     "name": "Not overridden",
                     "color": "#ffffff",
                     "index": -1,
diff --git a/plugins/UM3NetworkPrinting/NetworkPrinterOutputDevice.py b/plugins/UM3NetworkPrinting/NetworkPrinterOutputDevice.py
index 9b0eee7096..afeaadbb7a 100755
--- a/plugins/UM3NetworkPrinting/NetworkPrinterOutputDevice.py
+++ b/plugins/UM3NetworkPrinting/NetworkPrinterOutputDevice.py
@@ -306,8 +306,11 @@ class NetworkPrinterOutputDevice(PrinterOutputDevice):
     def _stopCamera(self):
         self._camera_timer.stop()
         if self._image_reply:
-            self._image_reply.abort()
-            self._image_reply.downloadProgress.disconnect(self._onStreamDownloadProgress)
+            try:
+                self._image_reply.abort()
+                self._image_reply.downloadProgress.disconnect(self._onStreamDownloadProgress)
+            except RuntimeError:
+                pass  # It can happen that the wrapped c++ object is already deleted.
             self._image_reply = None
             self._image_request = None
 
diff --git a/resources/qml/Settings/SettingOptionalExtruder.qml b/resources/qml/Settings/SettingOptionalExtruder.qml
index 07b15e404d..1f546b518c 100644
--- a/resources/qml/Settings/SettingOptionalExtruder.qml
+++ b/resources/qml/Settings/SettingOptionalExtruder.qml
@@ -20,7 +20,7 @@ SettingItem
         model: Cura.ExtrudersModel
         {
             onModelChanged: control.color = getItem(control.currentIndex).color
-            useOptionalExtruder: true
+            addOptionalExtruder: true
         }
 
         textRole: "name"