I am noticing that when I open a Windows application from either my OS X dock or from the VMware application menu, the application will open in Windows, but in a split-second after it opens it will lose focus. So, for example, when I open Quicken, it will open and the initial password window will pop up, but then that window will lose focus and I therefore have to click in the password window in order to start typing.
Just as a note, a similar behavior popped up in the 2012 Preview last year that was subsequently fixed. I would have to search back in the forums for that, but just something to note.
MBPr (Early 2013)
OS X 10.8.4
Fusion Tech Preview 2013
Windows 7 Pro (fully patched)