I agree, I was able to alt-tab out any number of times today to perform other tasks on my system.

Same here^

It is random. I found one way to eliminate the problem by clicking on the feedback link and keeping it open on the desktop. After that I can go to the mission editor and Alt+Tab back and forth with no issue.
It also seems to work when a document is already open on the Desktop.

OS: windows 7 64bit

I find I only have this problem when not running the script editor (ARMAEdit).
I had the same issue in OA but to a lesser degree.

This depends on wheter or not you have something to alt tab to in the desktop.

Close all programs and you dont have any pages where to alt-tab.

Keep browser open and you can alt-tab freely.

This issue was processed by our team and will be looked into. We thank you for your feedback.

Please keep the issue monitored to see when it is fixed.

I have the same problem. It started today after I updated to 0.56 stable. Of course I don't know if the update has anything to do with it or if it's just a coincidence. My OS is Win7 64 bit,too.

Anyway, have the devs found any solutions since mid-April or is the matter still being investigated?

In case someone is looking into this matter here is a little update:

I have deleted ArmA3 from the Steam library and downloaded the game again. No change, Alt-Tab still doesn't work. Steam verification confirmed that the game files are OK.

Then I changed from stable 0.56 to developer build 0.55 and Alt-Tab works again provided that another window is open on the desktop. It is not possible to Alt-tab to an empty destop. This would be nice if you want to open an application after having started to play Arma3.

For me it's possible to tab out of the game to empty desktop.
BUT as soon as I start (for example) Firefox from desktop I'm switched back to Arma.
Also if I already have another program running and alt tab to it and then close that program I'm switched back to Arma.
Really annoying.

Win 8, 64bit

Yes I get that as well it's really annoying when it takes control and puts you back in the game.

Issue closed as obsolete. If you encounter this problem again, please create another ticket. Thank you.