Labels can fail to disappear when the mouse pointer goes away


See GIF attached, where the label suggesting me to attach a photo to the room doesn't go away. I initially thought it was specific to this label but right before filing this issue I saw it happen with the label about per-room notifications settings in the room list (though this latter one seems to be more difficult to reproduce, whereas I can reproduce the former very easily).

I'm using https://develop.element.io in Firefox 83.0, and have sent logs.

Reproduce the stuck label on develop.element.io in Firefox, starting with the photo-attachment suggestion and then the per-room notification label in the room list. Compare pointer-leave behavior with the GIF and sent logs; done means both labels reliably disappear when the pointer moves away.

Written by the indexing model from the issue text.