Can I do sth when a window loses focus???

Hiding, Animating etc…//bow

Since you’ve been so specific, here’s another solution:

DestroyModuleConfig FE-LW:*
*FE-LW: leave_window doSomethingHere

Here’s another:

FvwmAuto 0 -passid -mleave "Silent SomeFunction action"

DestroyFunc SomeFunction
AddToFunc   SomeFunction
+ I WindowId $1 (SomeWindowTitle) $0

I prefer the FvwmAuto approach myself.

– Thomas Adam

[size=150]Thank you! The FvwmAuto solution works for me.[/size]