Potential approach to EnterNotify problem in window manager

[Ingo Bürk]

Hi guys,

at the i3 window manager, we have a separate system bar application
(i3bar), which is not integrated into the window manager. It can be
hidden and only be shown upon keypress.

This causes the problem that if the user puts their pointer "away" in
some corner, then shows the bar for a second and then hides it again,
X11 generates LeaveNotify for i3bar and EnterNotify for whichever window
is underneath the pointer. Since the user might have "focus follows
mouse", this causes said window to be focused, even though it's not at
all the intention of the user (they're not really looking to use their
mouse at all in this scenario).

Now, if i3bar was part of the window manager, we could obviously just
discard the EnterNotify in the window manager to avoid this. But since
they are separated applications, I'm having trouble thinking of a
possible fix for this problem. There (intentionally) seems to be no way
to suppress the EnterNotify on the underlying window. So before
concluding that this is impossible to fix I wanted to ask if anyone here
maybe has a smart idea?

Thanks!


Regards
Ingo