Running Xcode 9.4.1 on macOS 10.4.2, when I click on a combo box in a window, in the debugger I get an exception:

[General] The window has been marked as needing another Display Window pass, but it has already had 3 Display Window passes. Future marking as needing Display Window might be ignored.

Nothing appears to be complaining about ambiguous constraints, and searching for that message produced no hits.

Anybody have a clue what to look at?

Thanks,
John
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John Brownie
Mussau-Emira language, New Ireland Province, Papua New Guinea
Kouvola, Finland