do you run without a compositor? I get where you're coming from, but 'idle' can mean a lot of different things and redrawing the whole UI at 60hz is not necessarily 'not idle' nowadays.
I run with a compositor, which is exactly why it's so great for the application to just draw its window once and then the compositor has the window's contents as a texture. The compositor can do whatever it wants with that texture without involvement from the application.