Comment 48 for bug 329616

This has suddenly started happening to me in 11.04 after changing some session settings. There were a few things I did that could have led to the problem...
First I changed my GDM settings to log in automatically. Shortly after doing this I came back to the machine after it had been idle for a while and found the mouse not working properly, unable to switch windows by Alt+tab, etc. It seemed as if something had grabbed the mouse, as if a menu were open somewhere that I couldn't close. xwininfo, import etc would also complain they couldn't grab the mouse.
I restarted and X failed to start. I discovered at this point that a capacitor on the GPU (an nVidia) had failed, so I replaced with an ATI I had around, changed the drivers, got Compiz working again, etc.
With the ATI card it would always start up with only one monitor enabled and I'd have to turn on the other with xrandr. I tried logging out and clicking "save this session" in hopes it would stay that way, and I suspect this is where the trouble really began.
Saving the session didn't fix the monitor layout (I still have to use xrandr every time I log in), but now it takes a very long time to log in, the splash screen flickers a lot, and I get messages about the tray area losing focus. The mouse grabbing problem also comes back about once a day, and the only way to fix it seems to be to restart X. No amount of killing processes would get it working again.
In diagnosing this issue I discovered that every time I log in, for some reason there are 6 instances of xfdesktop, xfce4-panel and xfwm4 started. Killing these doesn't seem to help anything either.

It seemed like changing the login settings broke something to cause the mouse issues, followed by a conveniently-timed hardware failure that forced me to switch video drivers, and then checking "save session" on logging out broke more things. I've had trouble getting the session management to do anything useful, so this seems like the most likely culprit here too...