I don't think this is a matter of bugs. On Windows 7 (RTM, Enterprise), Fences do work quite perfectly, on dual screen setup and everything - provided I give up running Aero. Aero is a new environment to which Fences must be adapted.
With Aero, the icons get confined into designated areas, however, the fences themselves are not displayed. Also the double-click feature does not hide the icons.
Needless to say, whenever the fix to this comes, it won't be soon enough. 
Regards,
Damjan