Just a quick report, the Full Screen (F11) hotkey no longer does anything when pressed, and now users have to go into the ROBLOX menu to set it manually.
Also, it appears that ROBLOX doesn’t detect if your last game was played in full screen, it always launches in windowed mode.
I am not able to reproduce this issue at all, the hotkey is working as expected.
That’s weird.
I’m running Windows 8.1, you?
That’s weird.
I’m running Windows 8.1, you?[/quote]
Also running 8.1.
If your keyboard has extra ‘function keys’ which can be toggled with a button, which take over the normal actions of the Function keys, make sure they’re disabled. My sister has a keyboard with this ‘feature’ and it can be pretty irritating. 
The F11 hotkey never worked for me, granted I’m on a Mac. Normally it should be used as FN + F11, but still doesn’t work for me. My whole time on ROBLOX has consisted of manually going to the menu, Game Options and going into Fullscreen.