Its a shame a new issue was created for this. The problem has been
around for over 7 years and by creating a new ticket it looses just how
many people this affects.
https://bugs.launchpad.net/ubuntu/+source/unity/+bug/1295267
In my case, I have 3 monitors connected to a Dell Latitude laptop.
I can't believe this bug is still open. The report goes back more than
10 years.
Also the duplicate (bug 4286) mentioned above is incorrect, it points an
avifile issue.
This is a incredibly high security issue that should be fixed
immediately. Not only all the examples mentioned above by meany
