X stops receiving mouse clicks

[Emanuele Tamponi]

In data sabato 9 maggio 2009 12:29:56, Peter Hutterer ha scritto:
> we've seen this in Fedora as well (that's on server 1.5) but not been able
> yet to find the actual source of the bug. so far, it indicates a
> misbehaving client, but we haven't managed to find that one either.
> https://bugzilla.redhat.com/show_bug.cgi?id=488083
>
> Any hints on how to reproduce this would be much appreciated.

Well, the problem is that I cannot reproduce it myself: it just happens at 
random. I know, this makes it quite difficult to fix... so can you tell me if I 
can log something useful to send to the ml? A program in the background for 
example...

Anyway, I'll give you an information I discovered today and that may be 
useful.

It looks like the mouse focus remains in a certain window, and that window 
keeps it: this way, mouse clicks outside the window don't work. I'll explain 
with an example.

Now, I'm writing this message with the KMail Composer. This window has the 
focus: mouse input works in this window (menus, toolbars and even window 
decoration). If I try to use the mouse in another window, it will not work.

I discovered kinda a workaround this problem too. If I right-click on the 
window that has the focus, it "frees" the mouse until next click: so if I 
click on some other window, it will receive mouse focus... and so on!

To explain with an example: now I'm writing this message with KMail Composer. 
Mouse focus is on this window and cannot go outside it. But if I right click 
on this window, and then on, for example, the firefox window I've opened in the 
background, the firefox window will receive the mouse input.

So it looks like it's a problem of mouse focus and of windows keeping mouse 
focus even if they shouldn't. This may be related to X, to the Window Manager, 
or eventually on the Toolkit.

I exclude the toolkit because it happens on both Qt-based and GTK-based 
application... I'll try to install compiz or some other window manager and 
replace KWin, I'll let you know if the problem goes away.

If not, it's a problem related to X.

Cheers,
Emanuele