[xmonad] Mouse focus without entering window

[Ico]

Hi Xmonad,

I'd like xmonad to give focus to the window under my mouse cursor,
independent of entering or leaving the window. 

Consider the following use case: one workspace with two windows. The
mouse and focus are both in the left window. I use the keyboard to give
focus to the right window (alt-tab or similar). To give focus back to
the left window by mouse, I first need to move the mouse outside and
then back into the window. Instead i'd like focus to pop back to window
one as soon as I move the mouse. (Yes, I know I could/should give focus
back with alt tab again, but that is not the point

I have more similar use cases, some using multiple work spaces, where
I'd like to see he same focus behaviour.

According to #xmonad on irc some would consider this behaviour buggy,
which I can understand. Is there still a way to make Xmonad act like
described?

Thank you,

Ico

-- 
:wq
^X^Cy^K^X^C^C^C^C