From 138f77179dd6e1190dd8defc87858bbee5a57a6a Mon Sep 17 00:00:00 2001
From: Jack Ha <jackha@gmail.com>
Date: Thu, 8 Mar 2018 14:31:55 +0100
Subject: [PATCH] CURA-4400 fix errors when switch or adding to new machine

---
 cura/Settings/MachineManager.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/cura/Settings/MachineManager.py b/cura/Settings/MachineManager.py
index d6c4671691..5afecb8ef5 100755
--- a/cura/Settings/MachineManager.py
+++ b/cura/Settings/MachineManager.py
@@ -192,6 +192,9 @@ class MachineManager(QObject):
 
         # Update the local global container stack reference
         self._global_container_stack = Application.getInstance().getGlobalContainerStack()
+        if self._global_container_stack:
+            self.updateDefaultExtruder()
+            self.updateNumberExtrudersEnabled()
         self.globalContainerChanged.emit()
 
         # after switching the global stack we reconnect all the signals and set the variant and material references
@@ -299,14 +302,11 @@ class MachineManager(QObject):
         containers = container_registry.findContainerStacks(id = stack_id)
         if containers:
             global_stack = containers[0]
-            self._default_extruder_position = "0"  # start off with position 0, later on update the default extruder
             ExtruderManager.getInstance().setActiveExtruderIndex(0)  # Switch to first extruder
             self._global_container_stack = global_stack
             Application.getInstance().setGlobalContainerStack(global_stack)
             ExtruderManager.getInstance()._globalContainerStackChanged()
             self._initMachineState(containers[0])
-            self.updateDefaultExtruder()
-            self.updateNumberExtrudersEnabled()
             self._onGlobalContainerChanged()
 
         self.__emitChangedSignals()