Guard against race condition where a note-off gui notification comes right after the instrument has been disabled

qtgui/instrument.py

@@ -309,8 +309,9 @@ class InstrumentTreeController(object):
 
     def react_instrumentStatusChanged(self, instrumentStatus:dict):
         self.parentMainWindow.qtApp.restoreOverrideCursor() #Sometimes the instrument was loaded with a cursor animation
-        gi = self.guiInstruments[instrumentStatus["idKey"]]
+        if instrumentStatus["idKey"] in self.guiInstruments:
-        gi.updateStatus(instrumentStatus)
+            gi = self.guiInstruments[instrumentStatus["idKey"]]
+            gi.updateStatus(instrumentStatus)
         self._adjustColumnSize()
 
         #We also cache the last status, as we cache the initial data. This way we can delete and recreate TreeItems without requesting new status data from the engine
@@ -327,8 +328,9 @@ class InstrumentTreeController(object):
 
     def react_instrumentMidiNoteOnActivity(self, idKey:tuple, pitch:int, velocity:int):
         #First figure out which instrument has activity
-        gi = self.guiInstruments[idKey]
+        if idKey in self.guiInstruments:
-        gi.activity() #We only do a quick flash here. No need for velocity, pitch or note-off
+            gi = self.guiInstruments[idKey]
+            gi.activity() #We only do a quick flash here. No need for velocity, pitch or note-off
 
 
     def contextMenu(self, qpoint): #strange that this is not an event but a qpoint