diff --git a/gui/builtinContextMenus/commandFits.py b/gui/builtinContextMenus/commandFits.py
index 7433efbec..d97118297 100644
--- a/gui/builtinContextMenus/commandFits.py
+++ b/gui/builtinContextMenus/commandFits.py
@@ -26,7 +26,7 @@ class CommandFits(ContextMenu):
             if evt is not None:
                 ids = getattr(evt, 'typeID')
                 if not isinstance(ids, set):
-                    ids = set([ids])
+                    ids = {ids}
 
             if evt is None or not ids.isdisjoint(cls.commandTypeIDs):
                 # we are adding or removing an item that defines a command fit. Need to refresh fit list