So, it's basically like the summary. I have two monitors, and I'm running DayZ on my primary monitor. After alt tabbing (moving my cursor to the other monitor) and moving it back, the cursor is no longer locked to the game. This means that the cursor will trigger various hover effects on the secondary screen, such as;
-Taskbar miniature preview
-Making everything transparent (hovering on the rectangle to the far lower right on the screen in w7)
-Web pages hover effects.

This seem to apply only to viewing around, not moving ingame cursor around in the inventory. When the inventory is brought up you must "fetch" the mouse from the other screen(if it was there) to be able to see it and use it ingame.

I am not 100% this occurs every time i alt tab, but at least most of the time.
The problem persist throughout the gaming session, until i resatrt the game.
The ARMA II mod had the same issues.

Don't know what version of the game it is, but the time and date are:
2013-12-17; 01:40(AM) CET