Message panel problem in 108.1333

I'm in the middle of an ugly manual refactoring and so I have to
periodically do a full rebuild to see what I haven't fixed yet.

When I push the double green arrow control on the Messages panel to
rerun the build, it want to ask me a question and puts up a prompt. I
think it's asking if I want to do a rebuild or just a make but it's only
up for a fraction of a second before the entire panel disappears and
nothing else happens.