Custom Escape Menu not working?

[OneCoolDude]

I'm trying to create a custom escape menu.

I'm using this code: https://pastebin.com/uEQQ5fQw

This is what actually happens: Screen capture

It's visible only in the beginning, but what's actually happening throughout the video is that the actual game menu UI is popping up for a frame, and then disappearing. Not sure how to fix it as I thought PreRender is supposed to make it disappear before it even shows. I tried doing it with it just checking if the escape key is down, same thing.

[OneCoolDude]

Update*

I straight up just used this code and the menu still pops up for a frame. Still broken
hook.Add("PreRender", "Test", function()

gui.HideGameUI()

end)