Hello,

I have configured my gnome DE to lower a window when middle-clicking on
the title bar. (There are less and less programs that still act on this
setting, but that's a different story.)

I just noticed that when firefox is covered by another window (in my
case thunderbird) and the title bars are aligned (which is not that
uncommon at the upper edge of the desktop) and I lower the covering
window with a middle click the window moves below the firefox window on
button-press, then the mouse is over a tab and on button-release this
tab is closed. So the click has an influence on two windows and the
second one isn't even visible when I press the mouse button.

Additionally this is not always immediately obvious to notice that you
lost a browser tab. (I only noticed because I had an audio file playing
in that tab and the music stopped.)

Not entirely sure this is a firefox bug, the problem might actually be
in wayland or gnome?!

Best regards
Uwe