Occasionally, the AddEnum function fails.
The enum appears under the concept in black
font and generates many exceptions (even a hundred or so).
The exact conditions that cause SM to fail is unkown so far
(but the bug has occurred soon after loading the tree
upon freshly launching SM.)

The only way to gracefully recover is to repeatedly
hit 'OK' to get through the exception dialogs.
There should be some way to bypass or suppress
these repeated error dialogs.