1. Open any fullscreen windows program, eg web browser. Have it on screen.
2. Start the Arma3 launcher. Have it in focus, and the other program behind.
3. Set options to start Arma in windowed mode, without nopause startup parameter from the Arma3 Launcher. Click "Play" to start loading Arma 3.
3. Wait until the bottom line of text in the Launcher states: "BattlEye: Updating BattlEye service" or "BattlEye: Launching the game" (this happens quite quickly).
4. Switch focus to other Windows program, either by Alt+Tab or clicking on it. If focus is not switched before the floating Arma3 logo and loading info appears on the centre of the screen, the repro has failed and needs to be restarted.
5. Wait. Arma3 sounds will be heard once it has loaded, even though the web browser is in focus.
6. Press keys, eg tab, then up/down arrows, or spacebar. Note Arma3 sounds playing.