Slate is an "immediate mode" UI framework, meaning it redraws the entire UI each frame. This is great for very dynamic interfaces that are rich with graphics and animations, but results
in unnecessary processor usage when nothing in the UI needs to change. Using the Active Timer system in Slate allows it to enter a
Sleep state when no UI needs to update. The Active Timer feature should be utilized when working on editor UI, but not when working on UI for a game with a real-time viewport.
Slate sleeps whenever both of the following are true for a given frame:
A user action is any mouse movement, click, or key press.
The following diagram illustrates how the Slate application now ticks each frame:
This diagram shows how the editor's processor time changes once Slate sleeping is implemented.