Hello.

I have this problem after update to kde-4.3.
http://bugs.gentoo.org/show_bug.cgi?id=281615
I use Alt+1, Alt+2 ... and Alt+6 for switch between virtual desktops (6
desktops).
When I switch them quickly, and use Alt+tab, then keyboard stops working
sometimes. Remain works only Ctrl, Alt and BackSpace.
Repair this problem is restart KDE at all, or press Alt + left button of
mouse.
evdev version: 2.2.4.
Keyboard settings: setxkbmap -model evdev -layout us,ru -variant ,winkeys
This problem iterates at several computers. In console this problem don't
appears!
Thanks.

Reproducible: Sometimes

Steps to Reproduce:
1. Create 6 virtual desktops.
2. Bind Alt+1,Alt+2, Alt+3, Alt+4, Alt+5, Alt+6 for switch them.
3. Switch them quickly, and switch between application inside desktops at
Alt+Tab.
4. Keyboard stop working sometimes.

Actual Results:
Keyboard stop working, Remain works only Ctrl, Alt and BackSpace.

Expected Results:
Keyboard must work!

I have got the same problem (i'm on Gentoo also).
Did you read this ? I will try this "solution" next time i got this error.

PS: I'm working on a Dell Latitude D505 laptop.