I am having problems with KDE 'dropping' my keyboard. It happens periodically when using my gentoo box directly, but has become much worse when accessing via NX (from a Mac laptop). Some possibly irrelevant clues:

• it appears to happen more often when the system is under higher CPU load
• the mouse continues to work, but no windows will accept any kind of keyboard focus. kwin will not accept tabbing between windows.
• when working on the machine directly, I can ctrl-alt-F1 to get to a shell (obviously this does nothing over NX). so I think it is KDE and not xorg.
• am running kwin-4.3.5-r1, and KDE-4.3.5 generally. this problem definitely appeared after upgrading to kde-4.x, but I do not remember if it appeared in kde-4.2.
• sometimes the keyboard will reappear, but sometimes I have to kill my kde session.
• playing with accessibility options or window-focus-stealing options in system-settings under kde will often make the keyboard responsive again, only to drop it perhaps minutes later.
• I had read online this might be an evdev problem under X (again, I think this is KDE, not X, but will try anything). as a result, I have fiddled with my xorg.conf endlessly. I even deleted it entirely and let nvidia-xconfig have a stab at it, with no luck
• I am tearing my hair out over this.
• I have done emerge -e xorg-server and am right now doing emerge -e kwin, to rebuild all packages that might be relevant. no luck with the xorg-server rebuild.

any help appreciated. thanks,