Hi! Thanks for reaching out regarding that problem you encountered.
So, this dropdown has been modified to be only available when playmode is not active. This has been done because it's defining the behavior of the GameView when "entering" playmode, so disabling that settings while in playmode makes this more understandable. However, you can still change that settings while in playmode. Indeed, just Pausing the game will re-activate that dropdown without exiting playmode. Then, unpausing the game will directly re-apply that new settings :)
I hope this helps!
Feel free to reach out to us again if you have following questions :D