When Firefox is in fullscreen, whenever I click on any toolbar item, bookmark folder or extension, the dialogue box only stays open for a couple of seconds before closing. A similar behaviour happens when I right click (anywhere): the right-click dialogue box opens but only shows me options related to my extensions (for instance, ublock's "block element...") for a few seconds before disabling this section of the box. The dialogue box from the item I clicked on only stays open for a bit before abruptly closing without me asking it to do so. Basically, it acts as if I click somewhere else to close the dialogue box, although I don't. The amount of time the box stays open isn't fixed, but rarely goes beyond 2 seconds. The bug only happens when Firefox is in fullscreen. When it's in a reduced window, the box stays open as long as I do not click elsewhere. [https://bug1807243.bmoattachments.org/attachment.cgi?id=9309713 Here is a video recording in which I try to show the bug.] On the first half of the vid, I only click once on the items, and the dialogue boxes disappear by themselves. Second half of the vid, FF is in a reduced window, and the bug disappears: the dialogue boxes stay open until I clic This only happens on Firefox. Even Librewolf and Tor, installed on the same computer, don't have the same behaviour.