STR: 1. Open Aurora 2. Move the Panic/Forget button to Toolbar 3. Click the button a few times 4. Enter Fullscreen 5. Click the button a few times Expected results: The button works after toggling between Fullscreen and normal mode. Actual results: The button is stuck after entering Fullscreen. Notes: 1. I am not able to reproduce it regularly so it`s intermittent. 2. I was able to reproduce it only on Mac OS X. 3. Screencast showing the issue: https://db.tt/Y8Pe6U1c 4. Will investigate further for reliable steps.

Bogdan, did you find more reliable STR for what's going on here? When this happens, do you see any errors in the browser console?

(In reply to :Gijs Kruitbosch from comment #1) > Bogdan, did you find more reliable STR for what's going on here? When this > happens, do you see any errors in the browser console? Browser console is empty, but if I move the Forget button to panel menu after the issue happens, clicking on it will show 'viewNode is null panelUI.xml:186' in console. Yes using this steps I was able to reproduce every time, 9 out of 10 from the first try: 1. Open firefox with clean profile 2. Move the Forget button in the toolbar right in front of ‘back’ button (Any place in the toolbar would do) 3. Click Forget button to open the pop-up 4. Click Forget button to close the pop-up 5. Enter fullscreen using the double arrow button from top right 6. Click Forget button to open the pop-up Not sure if it helps but using an Aurora debug build I get this in terminal: https://pastebin.mozilla.org/6731597 Please let me know if there is anything I can help with.

(In reply to Bogdan Maris, QA [:bogdan_maris] from comment #2) > (In reply to :Gijs Kruitbosch from comment #1) > > Bogdan, did you find more reliable STR for what's going on here? When this > > happens, do you see any errors in the browser console? > > Browser console is empty, but if I move the Forget button to panel menu > after the issue happens, clicking on it will show 'viewNode is null > panelUI.xml:186' in console. > > Yes using this steps I was able to reproduce every time, 9 out of 10 from > the first try: > > 1. Open firefox with clean profile > 2. Move the Forget button in the toolbar right in front of ‘back’ button > (Any place in the toolbar would do) > 3. Click Forget button to open the pop-up > 4. Click Forget button to close the pop-up > 5. Enter fullscreen using the double arrow button from top right > 6. Click Forget button to open the pop-up > > Not sure if it helps but using an Aurora debug build I get this in terminal: > https://pastebin.mozilla.org/6731597 > > Please let me know if there is anything I can help with. Can you reproduce on Nightly? What version of OS X? (the steps above do not cause any issues for me)

Yes I can reproduce on Nightly as well, I used Mac OS X 10.9.5 (iMac&MiniMac) and 10.8.5 (iMac&MiniMac) with two different machines. If the steps don`t work from the first try they will (at least for me) if you repeat the steps.

So I missed the fact that you meant *while transitioning* between fullscreen and not fullscreen (either direction). I expect this is a problem in the PanelUI code... I'll add some debugging logging to try to figure this out.