If I hoover over a build queue item, I get a info box for that run. With the info from Gerrit plugin, these boxes can get quite big. (see screenshot).

IF the box then happens to overlap the upper border of the browser tab, the box misbehaves.
The misbehaviour depends on the browser  used:
Firefox: The box flickers.
Chrome / Edge Chromium: It pops up once, then disappears.

(Not sure if this is a browser or Jenkins problem)