update groups after deleting last track of a group

engine/api.py

@@ -552,14 +552,17 @@ def _reinsertDeletedTrack(track, trackIndex):
 def deleteTrack(trackId):
     track = session.data.trackById(trackId)
     oldIndex = session.data.tracks.index(track)
-    deletedTrack = session.data.deleteTrack(track)
+    with session.history.sequence("Delete Track"):
+        setTrackGroup(trackId, "") #has it's own undo
+        deletedTrack = session.data.deleteTrack(track)
 
-    if not session.data.tracks: #always keep at least one track
-        with session.history.sequence("Delete Track and autocreated Track"):
+        if not session.data.tracks: #always keep at least one track
             addTrack() #has it's own undo
             session.history.register(lambda tr=deletedTrack, pos=oldIndex: _reinsertDeletedTrack(tr, pos), descriptionString="Delete Track")
-    else:
-        session.history.register(lambda tr=deletedTrack, pos=oldIndex: _reinsertDeletedTrack(tr, pos), descriptionString="Delete Track")
+        else:
+            session.history.register(lambda tr=deletedTrack, pos=oldIndex: _reinsertDeletedTrack(tr, pos), descriptionString="Delete Track")
+
+    print (session.data.groups)
 
     updatePlayback()
     callbacks._numberOfTracksChanged()