Non-scenario objects

From AgeofWiki

This option toggles visibility of Non-scenario objects in the Editor.

Non-scenario objects are things like cinematic blocks, Revealers, Pop blocks, path blocks, Native Obstructions, and cinematic cubes that are normally not visible at all during game play. They are normally visible in the Editor, but you can use this to hide them. Useful for taking screenshots of mapwork or eye-candy from within the Editor.