Bit hard to explain, but let me try. I'm currently running a Fedora rawhide kernel with debugging enabled, which makes interactivity a bit slow, and it makes this issue much more obvious, though I think it always exists in theory.

It seems like there are two 'stages' to switching active windows. If I've been working in one for a while, then when I switch to another, the title bar of the new window always gets the 'I am now active!' change immediately - it stops being greyed out - but - the rest of its elements stay greyed out for a fraction of a second longer (almost imperceptible when I'm using a non-debug kernel, but noticeable when I'm using a debug one).

If I hit alt-key-above-tab during the time the new window appears to be active from its title but not from its contents, the action applies to the *old* active window, not the *new* one.

Upshot, if I have two Evolution windows and two Firefox windows and I'm trying to switch between the Evolution 'compose a message' window and both Firefox windows, I keep winding up with all the wrong windows active :/ It seems like a very corner case-y bug, but I'm actually running into it daily at the moment.

There's not a very obvious fix, I guess, since other people might be used to waiting for the other window elements to go active and would be confused if the behaviour were the other way around - maybe not everyone focuses on the window title to know when a window is active, the way I apparently do. Perhaps alt-key-above-tab behaviour could be temporarily suppressed while a window switch is between stage 1 and stage 2, or something?