Can't return to game after alt+tabbing.

I'm having a problem where, when I alt+tab out of the game in fullscreen I can't return but, can still ear everything that's going on and I can ear sound effects and the anouncer clearly. I can switch to borderless but when I left click the screen in borderless the screen flickers and my computer is not that good so i need to play in fullscreen to get optimal fps. If anyone knows how to fix this i would be very grateful.
Report as:
Offensive Spam Harassment Incorrect Board