What happened to "ALT+BACKSPACE" in Ubuntu ? How to restart Xorg ?

We all know old friend  alt+backspace which forced the XORG to be restarted when the computer screen was frozen .
and also the other old friend CTRL+ALT+DELETE , which is also disabled .

  What happened to Alt+Backspace in Ubuntu 11.10 ? (How to restart the X in ubuntu)
in pervious versions of Ubuntu (and other Gnome-based linuxes) , whenever the X crashed (the graphical window system manager) we would hit Alt+Backspace and the X would be restarted .

However , in the new versions of ubuntu, alt+backspace  doesn't work anymore and it been replaced by Alt+Printscreen+K
which is better . why ? because ALT+Printscreent+K combination could be caught by Kernel when the whole X is totaly gone, (remember those times that Alt-backspace wouldn't work ? it was because it was totaly gone , but now Alt Print Screen would be sent to Kernel which is better idea) 


Another explaintion of this change is, nowadays lots of applications use ALT+something as short cut and it would lead to restart the X by accident and possible data loss .


What happened to CTRL+ALT+DELETE , How to call System Monitor  or Kill a process or Log out in Ubuntu 11.10?
The CTRL+ALT+DELETE has been replaced by "CTRL+ALT+BACKSPACE" .
which it simply calls system monitor , so you could see the Ram usage and also the processes and kill them or End them or Map their memory usage .