I'm seeing this as well, although it's not limited to when the right mouse button is pressed. Basically, even though I'm in full screen mode I get mouse activity on the second monitor. This happens when I'm using maps and menus, (akin to full screen windowed mode), but also when I'm playing the game. The difference is that when I'm using menus the mouse cursor is visible as it moves on my 2nd desktop, and when I'm playing the game itself the mouse cursor is not visible, though still active. The reason I know this is that I have a desktop gadget showing the weather that has a "mouseover" effect, (aka tooltip, I think), that gets activated once in a while. Likewise, my taskbar is set to auto hide, and it will become activated when the mouse cursor is moved to the bottom of the 2nd desktop. This persists when gadgets are not active, by the way. I'm running an ATI card on windows 8. If someone is looking into this, I'd be happy to provide more information.