Open the attached testcase in TOT and hover over the big box. The transitions start as they should. When you unhover, they jump back as they should. But if you quickly hover again, the transitions pick up where they left off. It's as though they're still running.
Created attachment 30914 [details]
Ah, happens on TOT, so not hardware.
Created attachment 31301 [details]
Patch with test
Transmitting file data .......
Committed revision 44696.
*** Bug 26165 has been marked as a duplicate of this bug. ***