Shift + Backspace restarts X?

[thephotoman]

After upgrading to Edgy, I have noticed that once again, someone turned 
on the option to have X restart by pressing shift + backspace. 
Unfortunately, both keys get used quite heavily in my work, and the odds 
of pressing the two at the same time are fairly high.  How do I disable 
this functionality so that it doesn't bother me again?  The only key 
combination that I expect to restart X is ctrl + alt + backspace.