TOAW 3 question.

[fluidwill]

Thats the range(s) of your ranged weapons, aircraft, arty and in modern scens, AA (SAM's). The button cycles thro' range of selected unit, all units (as above), "normal" and "hide all units" for when you want to check out the terrain.
I usually do my turn with "selected unit range" on and then put all unit ranges on for a quick check at the end.
NOTE: I think the range comes up wether your units are in the correct posture (dug in, reserve etc) to support or not so a neat little circle on the map does not mean your units are getting fire support, mearly that the arty unit (say) is in the right place.
Keep asking the questions, and that IS a new feature and yes, i think its a good one.
Cheers