Vista - Mouse scrolling keeps sticking in Win 7 guest

Hi

I have Vista as host, already had XP as a guest, and have just installed Win
7 beta as a guest.

In the Win 7 guest, when I try to use my mouse wheel to scroll, it keeps
"sticking", i.e. |I roll it and the scrolling starts to start, but then
stops and it takes a couple of turns of the wheel to get going again, for
one more move, then sticks again.

The mouse is a MS optical wireless one - but shows up in the gusts as a PS2
mouse. It works fine in the host and in the XP guest.

Is this going to be a Win 7 beta issue or a VPC one.?

I've tried googling for the issue but found nothing so far.


Thanks