Why is Slate UI eating ~17ms in a basically empty project?

I have a scene with a plane that serves as the floor and three lowpoly shapes sharing the same shader. Everything is unlit, simple and there is no UI. I open up stat GPU and I see that something called Slate UI is taking all of my frame time. What’s going on here?

273266-what.png

If you are running the game in editor that is the editor UI which is rendered by Slate. Try running your game in standalone.

That’s probably the Editor, profile with Standalone (or Packaged) as they have their own process.