12.04 Window Manager Crashes on Boot
After a month or two of using 12.04 Ubuntu has developed a very annoying problem. On boot it all looks ok however all of the window title bars and menus become unclickable after the second app is launched, making it impossible to switch apps. Also mouse clicks fail to register in all but the previously active window. That window carries on being responsive as normal. The unity bar is also not clickable.
To work around this. I have to press ALT-F1 then login and run sudo killall Xorg. This kills X and causes it to restart which then works normally for an hour so. However eventually the same issue occurs. If I run top nothing appears to be maxing out the CPU.
Presumably an update has caused this. So I decided to update everything and then select the latest propriety Nvidia driver via the Hardware Manager. This hasn't solved it.
Any ideas what to try next?