Possibly Relevant Information:

• XUbuntu 12.04 LTS (precise)
• XFCE 4.8
• AMD Graphics (Kernel driver in use: fglrx_pci, Kernel modules: fglrx, radeon)

The primary symptom of this issue has been my active rdesktop session to stop responding while everything else appears to work normally. I have been killing rdesktop and re-launching it, with it freezing after a seemingly random time period. The fastest was within seconds. The longest was a couple hours, although it's usually within a few minutes.

That being said, I have occasionally seen the terminal and web browsers also become unresponsive to keyboard input. They respond to clicks and will accept middle clicks (to paste text) without issue while remaining unresponsive to the keyboard input.

I have been able to restore all functionality, including rdesktop, by switching workspaces and typing on the other workspace, then returning to the original workspace.

What is being reset when I do this? What does this work-around/solution indicate may be the problem?