#1 Pattern won't delete

[Neil Earnshaw]

When I tried to delete a Pattern in my Demo doc, it quietly refused
to delete. Haven't been able to replicate it with a fresh document.

Immediately after deleting the MicrowaveOven pattern in the
browser, the pattern stops responding to context menu requests in
the browser. Click away from the pattern and back to it, and it
once again responds to context menu requests.

Saving the file doesn't change the document's behaviour.

Defect may be due to a save with a model that was corrupted
while modifying the code generator to store generated files in a
directory named after the Pattern that owns them.