Why when I put a GUI size on 1,0,1,0 there is a top bar that wouldn't hide?

[nomcell (Katlepic)]

I’m trying out some GUIs and I cannot find a way to hide the top bar, how do I do so?
Example:

When I looked up a way to hide it I only found a way to hide the chat and not remove the topbar so the GUI could go through.

[chicken_boil (CorgiPlayz)]

In your ScreenGui enable the IgnoreGuiInset and it will be cover the topbar