Part of macOS

`WindowServer`Screen drawing

○ Leave it

Draws everything on your screen. Busy when windows move or video plays.

What it is

Puts every app’s windows together on the display. More displays, transparency and animation make it work harder.

Why it might be busy

Video is playing, windows are moving, or several displays are connected. Usually while that’s happening.

If you stop it

Stopping it logs you out straight away and closes every app. Leave it.

○ Leave it. Part of macOS, or something that starts again by itself. You never need to close these.

From Procession’s guide, in the words the app shows.