Steam overlay in game - grayed-out

The game says to "turn on the steam overlay in-game" in settings, but it is grayed out.

 

You need to enable it in Steam options. Then you can turn it on and off at the game level.

 

Hello, my Steam overlay is activated and the setting is set to one in rF2's properties, but I still can't dispay it nor access the ingame store Is there a fix please ?