Mouse focus stealing bug

Jan Pokorný jpokorny at redhat.com
Tue Sep 10 19:47:28 UTC 2013


On 31/08/13 09:36 +1000, Peter Hutterer wrote:
> On Fri, Aug 30, 2013 at 01:19:54PM +0200, Maros Zatko wrote:
>> Hello dear Fedora comunity,
>> 
>> I've hit very weird bug which happen to get very urgent now.
>> Something (very likely GTK{2,3} but not sure at all) is stealing my
>> mouse focus so that I cannot click anymore. Symptoms are in range
>> from being able to click once or several times AFTER switching
>> desktop (tag), to being able to click only with left button (with
>> right being totally unresponsive) to not being able to click at all
>> anymore until I kill Xorg.
>> 
>> Killing Xorg was *the fix* -- for you to understand, after reboot I
>> *had* to kill Xorg session three times, with spawning some GTK app
>> in between runs so that I hit the issue and Xorg restart had the
>> right effect.  What happens now is that Xorg restart are NOT
>> helping any more, i.e.  after that it "works" for about 5 minutes
>> and then it get progressively more and more wrong until I cannot
>> click any more.
>> 
>> My nowadays combo is Xmonad with nm-applet and some other basics
>> plus firefox, xchat, pidgin and some gnome-terminals (and couple of
>> other random stuff). To hit the issue is enough to spawn xchat and
>> firefox in a clean session.
>> 
>> I've been hitting the very same issue before when I was using
>> Awesome WM, but I thought it was its issue so I've picked xmonad
>> but after some time the same issues returned.
>> 
>> So, dear Fedora community, I beg you for help. I have no idea how
>> can I fix this, nor how can I debug it. Any help would be really
>> welcome.

Started to occur to me from time to time as well (LXDE at F18, inputs come
through synergy).

Last time, I think it started in connection with Firefox, and
fortunately it stopped with exiting Firefox.  In the meantime,
the treatment was to either switch to another virtual desktop
(and I am not sure if I used to right-click anything here) and
back, or to right-click bottom panel.

> sounds like a stuck grab. that can be a bug in the server or the
> application, but it's notoriously difficult to debug.
> 
> grabs are triggered by keyboard shortcuts, popup/dropdown menus and by
> simple button presses (i.e. drag and drop usually triggers a grab). 
> 
> generally if grab is stuck, the client with the grab still receives events,
> so you may be able to narrow it down by clicking and hoping that _something_
> responds to the click. that is the client with the grab then.

Yep, it looked like intended client was overriden, at least for
the part of the observed behavior.

> You'll have to figure out a reproducible test case because there are so many
> factors at play and the code is so convoluted that debugging this otherwise
> is almost impossible.

Unfortunately.  And backtracking which update introduced this issue would
be unrealistically time consuming provided that the reproducer seems
to be quite random.  So my hope is it will go away the same way it
arrived.

-- 
Jan


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