I'll throw in a "me too!" for all the folks that this is driving nutz.
I have tried several options including:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced - TaskbarAl <- Note that the term is Taskbar ALignment, NOT A (Capital i)
HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows\MenuDropAlignment
when I reboot, it resets in the registry R-Click Menu back to the extreme Left.
Is there a window location/pixel size/offset key I'm not aware of or can't find?
Any help would be great