Cannot Close Popout Window After Force Close and Restore

[rthaut]

From: https://addons.mozilla.org/en-US/firefox/addon/youtube-popout-player/reviews/1444098/

if you have the window open and then force quit Firefox for any reason then when you re-open it (with the restore session checked) the pop out window is now missing the "top bar" and you cannot close the window.