Why is the PlayerMouse not firing KeyDown when F key pressed?

This used to work fine, but last week or so I noticed that the F key control wasn't working in my game.

I just now did a simple test:

function keydown(k)
	print(k);
end

m = game.Players.LocalPlayer:GetMouse();
m.KeyDown:connect(keydown)

... and "f" wasn't printed when I pressed the 'f' key (though everything else works).

Why is the f key now protected?

Can I do something to get around this? Will using a tool work? Can I do that will hiding the ROBLOX tool GUIs and avoiding other UI annoyances?

To get around protected keys, you will unfortunately have to use KeyUp. This is what I did when I wanted "/" to be a key that worked in my game. Sorry if you REALLY want to use KeyDown for "f," this probably wasn't the answer you wanted lol. If that is the case then I suggest sending a message to roblox about your request to fix these protected keys. (And yes, "f" is one of my hotkeys in my game too so "f" will work with KeyUp, but I figured I'd use "/" as an example xD)