My Documents relocating spontaneously
 

I use TweakUI to relocate my My Document folder from its default
location in "C:\Documents and Settings\Matt\Matts Documents" to
someplace else. Everything works fine, but then a day or two later
something is spontaneously relocating My Documents back to its default
location. No files are actually moved nor is anything deleted and I
can just manually use TweakUI again to reset it where I want it, but
it's annoying. How can I find out what is changing that setting "on
its own" and prevent it from happening?