I use Windows 7. My second monitor is on the right side of the primary monitor.

I am unsure whether starting the game in windowed mode, then switching to full-screen, or something similar, might be a factor here.

Good to see this has been reported. I'm surprised there is not more chat on this topic. The task status is just "reviewed" and not "assigned"? How odd.

Strange that A2 had this feature working fine, but not in A3.

I think in A2, when you pressed Esc to open the main game menu, the mouse would appear and the mouse boundaries were then turned off, so you could click on a 2nd monitor to switch to another program.

But now in A3, the mouse boundaries are turned off all the time. In one game I was switched out of A3 5 times and given that the fire button is associated with the mouse button click, the consequences of this to the gameplay can be detrimental.

Even if you don't get switched out, it's also annoying as you turn/look around in game seeing all of the other active program windows "highlight" or show a selection scroll or seeing your task bar hints or nested windows lists appear in game.

I'm almost glad to see I'm not the only one with that problem.
It's a really annoying issue that leads to the game minimizing and accidentally clicking on another window on another monitor.

I could observe strange mouse movement behavior when doing this:

With these steps I can reproduce the error easily in no time (min. 2 Monitors needed to reproduce):

• Load a game/any map/scenario, open your soldiers inventory with I(i) button
• mouse should appear in the center of the monitor the very 1st time
• move mouse slightly (not persistent) any direction, close inventory again with I button
• open inventory again, don't move this time
• close inventory again, and open it up again
• now every time you close/-re enter inventory the mouse will shift further.
• repeat every direction you want, when it goes towards the direction of the other monitor it's when the game minimizes because the mouse is out of bound of the game's monitor.

I found a tool that will lock the mouse to the active monitor, even got a profile management, so the mouse can just be locked to active screen while Arma 3 is the active window:

http://sourceforge.net/projects/mousenitor

For now a good solution to me until BI will fix this issue.
Hope I could help in any way, cheers :)

Related to this:
http://feedback.arma3.com/view.php?id=5076

Can anyone recommend a fix for this in Linux? It's basically unplayable without it...

Can anyone recommend a fix for this in MAC OSX? It's basically unplayable without it...