I am not sure what I did, but for some reason Ctrl-Alt-F? bindings are broken on 64-bit xen desktop machine (but not on my laptop (32-bit, no xen)). Both machines are (mostly) up-to-date and running CentOS 5.9. I rarely hop to different Virtual Consoles (eg Ctrl-Alt-F1 ... Ctrl-Alt-F7), but today I wanted to go to the main console to watch some kernel verbage (I was checking something with hot-swap SATA disk). I discovered that I could not switch back to my X11 session (Ctrl-Alt-F7)! I did some googling, but did not find anything. So far as I can tell, I can switch to one of the other VT (Ctrl-Alt-Fn) *from* VT7 (my X11 session), but cannot then switch to any other VT from there, using the Ctrl-Alt-F? key bindings. The chvt command works, but the keybindings don't. It is most strange. I know this used to work (and still does work just fine on my laptop, running much the same system, including the same X11 configuration, with the same desktop setup (plain fvwm in MWM compatibity mode, same keybindings, etc.). Other than different video cards (and thus different X11 drivers) and 32-bit vs 64-bit and with xen virtualization on the 64-bit desktop box, the system setups are virtually identical.