User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:37.0) Gecko/20100101 Firefox/37.0 Build ID: 20150402191859 Steps to reproduce: Hang when trying to minimize a browser window when the flash player is in full screen in another one. NOTE: This is done with a multi-monitor setup. I actually have 4 monitors. That being said, I recall that I tried minimizing a window which was opened in a monitor connected to a different video card than the one where the Flash player was in full screen. Actual results: Firefox hang Expected results: Minimize the other window.

Do you have a hanglog from about:crashes?

No because when it happen, I have to kill the process from the task manager. You may look at these one from my about:crashes page. https://crash-stats.mozilla.com/report/index/bp-b5d1a12e-7499-4251-9a43-dc70c2150430 https://crash-stats.mozilla.com/report/index/bp-b2a419e5-d76e-4c9c-bb85-87bf22150418

Can you reproduce it always with these STR? If yes, you can try use this information on Mozilla Wiki ( https://wiki.mozilla.org/Flash/Hang_Debugging ) to collect full memory dump.

This is the top crash signature for Firefox Dev Edition 40.0a2.

To be clear, this is the generic hang signature that you always get when Firefox hang detection kills Flash, and is hopefully mitigated by the IPC work that's in the Firefox pipeline. It would be great if we could get the reporter to confirm whether or not this reproduces in Nightly, given that their config is somewhat unique.

I'm closing a lot of bugs which are filed as Adobe Flash bugs which are either irrelevant, not actionable, or not serious enough to track in the Mozilla bug tracker. For the most part, Flash bugs should be filed in Adobe bugbase, and we'll only track a few highly-critical issues in the Mozilla tracker.