Layout test fast/events/popup-when-select-change.html has been timing out on the GTK bot since r222392 "Use high resolution timestamp for event time". Since it's a timeout there's unfortunately not really any results to post here. Updating expectations accordingly. I also see one crash in the history, so I'll add a crash expectation too.
This is likely the same issue as Bug 177449 given that the test is submitting forms.
Good point, I'll mark it as a duplicate as I haven't committed the test expectations yet. *** This bug has been marked as a duplicate of bug 177449 ***