Hello, there are bad websites that open popups when you click on video for changing position of pause/play. When video is in full-screen mode and such site opens a popup, then there is no way I could figure to close the popup tab and switch back to video. I need to close browser and only then I can close the ad tab and use video again, until next popup comes up. If video is not in fullscreen mode, then I can see address bar and the tabs button by scrolling up. But if video was once set to fullscreen, then the above described issue happens. I think the following changes would make issue fixed: * there should be a setting to always open popups in background tabs * leave full-screen video mode immediately when a popup is opened (when popup is opened in the foreground) * there should be a button in browser menu to access tabs Example video: http://kinofen.net/filmi/17834-a-ring-by-spring-prsten-do-proletta-2014.html P.S. btw I see chrome using less energy to play video than firefox, not sure if this is a known thing

I was able to reproduce this issue on Samsung galaxy Note 4 (Android 5.0.1) and Asus ZenPad 8 (Android 6.0.1), on the latest Nightly 54 (2017-31-01). The issue doesn't reproduce on Chrome, where the pop-ups are opened in new tabs, switching out from full-screen.

This looks to be HLS video.

TBH I think switching you off full screen to open a new tab is undesirable. It would make more sense for firefox to open the thing in a new background tab with the on-screen option for user to switch to that new tab if desired. If I watch something in full screen it's unlikely to want switching off it to a new tab.

Mass wontfix for bugs affecting firefox 52.

This is a P1 bug without an assignee. P1 are bugs which are being worked on for the current release cycle/iteration/sprint. If the bug is not assigned by Monday, 28 August, the bug's priority will be reset to '--'.

Mass change P1->P2 to align with new Mozilla triage process.

We have completed our launch of our new Firefox on Android. The development of the new versions use GitHub for issue tracking. If the bug report still reproduces in a current version of [Firefox on Android nightly](https://play.google.com/store/apps/details?id=org.mozilla.fenix) an issue can be reported at the [Fenix GitHub project](https://github.com/mozilla-mobile/fenix/). If you want to discuss your report please use [Mozilla's chat](https://wiki.mozilla.org/Matrix#Connect_to_Matrix) server https://chat.mozilla.org and join the [#fenix](https://chat.mozilla.org/#/room/#fenix:mozilla.org) channel.