diff --git a/cura/ExtruderManager.py b/cura/ExtruderManager.py
index 34dbfd7c0c..3477a3175f 100644
--- a/cura/ExtruderManager.py
+++ b/cura/ExtruderManager.py
@@ -5,6 +5,7 @@ from cura.Extruder import Extruder #The individual extruders managed by this man
 from UM.Application import Application #To get the global container stack to find the current machine.
 from UM.Logger import Logger
 from UM.Settings.ContainerRegistry import ContainerRegistry #Finding containers by ID.
+import UM.Signal #To notify other components of changes in the extruders.
 
 
 ##  Class that handles the current extruder stack.
@@ -16,6 +17,9 @@ class ExtruderManager:
     ##  The singleton instance of this manager.
     __instance = None
 
+    ##  Signal to notify other components when the list of extruders changes.
+    extrudersChanged = UM.Signal()
+
     ##  Registers listeners and such to listen to changes to the extruders.
     def __init__(self):
         self._extruders = [] #Extruders for the current machine.
@@ -49,6 +53,7 @@ class ExtruderManager:
     def _reloadExtruders(self):
         self._extruders = []
         if not self._global_container_stack: #No machine has been added yet.
+            self.extrudersChanged.emit() #Yes, we just cleared the _extruders list!
             return #Then leave them empty!
 
         #Get the extruder definitions belonging to the current machine.
@@ -60,4 +65,5 @@ class ExtruderManager:
                 Logger.log("w", "Machine definition %s refers to an extruder train \"%s\", but no such extruder was found.", machine.getId(), extruder_train_id)
                 continue
             for extruder_definition in extruder_definitions:
-                self._extruders.append(Extruder(extruder_definition))
\ No newline at end of file
+                self._extruders.append(Extruder(extruder_definition))
+        self.extrudersChanged.emit()
\ No newline at end of file