Running unclutter without "-noevent" causes focus problems for Firefox and Thunderbird

Status changed to 'Confirmed' because the bug affects multiple users.

If I use a new firefox profile, it works as expected. The old profile still has focus issues.

I have similar issues with both Firefox 25.0.1 and Thunderbird 24.1.1. I have multiple extensions installed on both, but neither has a single same extension (so either this may be caused by multiple different extensions or something else is going on).

Additional info:

- I have been hit with this problem every now and then since around Firefox 10 and Thunderbird 3. I think this is a problem in Ubuntu XUL core because the problem is visible with both Firefox and Thunderbird.

- I have been hit with this problem using at least Gnome 2.x, Unity and Cinnamon desktop environments so I'd guess this is not related to the window manager. I haven't used KDE long enough to verify if this problem is visible in that environment, too.

- Since I have reduced the system latency(*) I've hit this problem more often; I guess it's some kind of race condition between some paraller threads or processes doing something. The system is running on i7-3770k with HT enabled (without overclocking).

(*)
mira@desktop:/proc/sys/kernel# grep . sched_*
...
sched_latency_ns:200000
sched_migration_cost_ns:500000
sched_min_granularity_ns:100000
sched_nr_migrate:3
sched_wakeup_granularity_ns:50000

I guess this may be caused by package "unclutter" (which I do have installed):

https://forum.kde.org/viewtopic.php?f=111&t=117704&start=15
https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/1234470

I will try running it with '-noevents' and if that does not fix the issue, I'll try living without it and seeing if that fixes the problem.

Are there any news about this bug?

After a few days, my new profile had the same problem. As browsing is an essential task, I had to switch to gnome3 and I haven't had this issue for months. Probably, the problem is related to unity.

Carlos, as per Mikko's comment's links,, it's not just Unity, but also in Kubuntu/KDE. Did you try killing unclutter, or running it with -noeventst?

No. I may take some time before trying it, because I don't want to lose all my workspaces in the next days.

I am experiencing this problem with both Firefox and Thunderbird (and have lost many e-mail messages because my typing suddenly went to the index window and was interpreted there as a "delete").

Contrary to the original poster, I have the problem only with keyboard events, never with mouse events. Klicking, dragging, marking all works fine on the foreground window. Key strokes suddenly start going to the background window. Switching the foreground between windows does not help. Closing and restarting the whole application usually helps.

My workaround in Thunderbird is to create an empty folder and switch the index window to it before typing a message, so the stray keystrokes cannot do much damage. In Firefox I use tabs instead of windows.

I was being driven up the wall with this problem for a long time (even in a non-Ubuntu distro) and couldn't for the life of me figure out what was going on until someone mentioned Unclutter! (I was blaming the window manager, GUI toolkits, etc.--I never would have suspected unclutter.) It does indeed seem to cause problems.

I sort of worry that -noevent could potentially cause other problems, though. Apparently unclutter uses a lot of funky hacks to do its work which causes weird things to happen in general. There's a rewrite of it using the x11-xfixes extension which looks like a much cleaner solution: https://github.com/Airblader/unclutter-xfixes

I found it fairly easy to build, and so far I haven't seen any problems or weird behavior while using it. It would be nice if it could be considered for inclusion in the Ubuntu repos.