What it does
Pauses shaking whenever the display is off or the screen is locked.
How it works
Shake It On listens for `com.apple.screenIsLocked` / `screenIsUnlocked` notifications and falls back to CGSessionCopyCurrentDictionary's `CGSSessionScreenIsLocked` key. When `Allow display to sleep while shaking` is on, this pause condition is bypassed automatically — that's the whole point of display-sleep mode.
Where to find it
Settings → Paused When → Display is off or locked. On by default. Greyed out when display-sleep mode is on.
When to use it
Leave on for normal operation. Turn off (or use display-sleep mode) when you specifically want background tasks to keep running with the screen off.