Gap in web player (Android firefox)

[stkw0]

In the web player under Android Firefox there is a gap at the bottom. Usually there is the search bar of the browser but when scrolling it hides and when changing from task to task sometimes the web app doesn't show correctly, see image below

[epoupon]

I pushed a tentative fix, please reopen if needed

[stkw0]

yesterday it happen the same running v3.52.0, though it's the first time I have seen it since running v3.52.0, seems it happens less often now.