I too found this to be the first post that speaks of exactly what I'm experiencing with shortcut keys not working. Here's what I have noticed thus far:
I can remove the key combo and click save then re-enter the combo or remove and recreate the shortcut altogether and they will work just fine. However what I have noticed is the problem is present when I reboot the OS as they no longer work after that event. The shortcut itself works fine when double clicking it however the shortcut key strokes no longer work. I was really looking forward to this feature based on the increased efficiecy.
I will keep looking to see if I or someone else can figure this out then post back here. I probably need to rely on someone elses fix that know a little more about the inner workings of Win 7.