How do you disable shift lock for gui's?

I have shiftlock forced on the player when they join but I want to know how to disable it when they open a gui so their mouse isn't locked.

local mouse = game.Players.LocalPlayer:GetMouse()

mouse.KeyDown:connect(function(key)
	if key:lower() == "g" then
		script.Parent.Enabled = not script.Parent.Enabled
	end
end)

this.ShiftLock = true