How to draw GUI window ontop of controls?

The GUI.BeginWindow docs state:

“Windows float above normal GUI controls,” I had assumed this is why it needs a contents callback, because Window draw is deferred until the end of the OnGui call.

However thats not what I am seeing. Instead, I seem to be seeing a strict back to front ordering by order of draw calls. The window and its contents seem to be getting drawn to the frame buffer immediately on the call to GUI.Window

Are the docs incorrect? Am I somehow misinterpreting them?

I can fix this by implementing my own depth sorting but that will really complicate my code so I would rather not.

Alright, apparently GUI.color can only decrease alpha, never increase it.

I had to make a custom skin with opaque windows.