Hello all,

(I changed the subject line, since it looks very
much as if the issue is in this dialog.)

Thanks to all who commented. Knowing that it's
specific to having 'Use MPCORB' checked is huge; that
narrows down the chunks of code I need to look at. I'll
report once I've figured out something. If you spot
any patterns that might be clues to this bug (or spot
other bugs, for that matter), please let me know.

-- Bill