Toggle Range Rings

From AgeofWiki

This option is apparently intended to let the designer display or hide the range of ranged units and buildings on the map in the Editor.

The major purpose of range rings is to help the designer put adequate distance between ranged units/buildings and nearby enemy units on the map, to prevent them from attacking one another prematurely. For example, if you're making a fort siege scenario, you may wish to place gold mines, berry bushes, and treasures outside the range ring of the fort so that villagers and noncombat units will not be attacked while gathering resources.

This option, along with LOS Rings, appears to not work in the Editor.