Cannot disable "windows key" behavior from Fusion 5

Can someone tell me how to disable the "windows key" function from within a VM running Win 7.  For example, what I *used* to be able to do was hit "command-tab" to switch between my VM and other apps running on OS X.  Now, the "command" key on my MBP defaults to the "windows key" and always opens up the start menu in Win 7.  I've disabled the key mapping in the preferences but that didn't make any difference.

So, the behavior is:

1. I'm in my Win 7 VM

2. Hit "command-tab"

3. The start menu in Win 7 comes up but I can still move to a different OS X

4. Come back to Win 7 VM and the start menu is up

I know this sounds silly but it's driving me crazy.

Thanks