I've not seen the mouse activate stuff, other then what I click on.

If you press your in game GUI key, it will bring up all the regions where a mouse click is broadcast.
You might also have a mouse click, set as the hotkey for something.
Not sure on either, but I'd guess it was one of the two.

I'm not totally familiar with Vuhdo; can you set it to respond to "any" click, rather then just clicks on its frame?