Yup me too, idk what it is either :v
Maybe an invisible holder from the Default Roblox GUI, try disabling all Core GUI’s and see if that “gap” still there
I suppose what you mean is when you’re editing UI in Studio the whole screen will be covered, but if you playtest in Studio or in an actual server it gets shifted lower because of the Topbar area?
You simply need to enable the property IgnoreGuiInset of the ScreenGui you’re using if you want that area to be covered too.
Likely to prevent any unknowing developers from accidentally covering up any important part of the topbar, and then being confused and frustrated over “It’d be nice if Studio would show me those icons as I’m working on it so I don’t have to guesstimate their positions all the time!”