What's the green region on the timeline?

[dantarbill]

I've been on SONAR for a very long time...and only recently switched over to Cakewalk (by Bandlab).

I'm seeing something new (to me) on the timeline that I don't yet understand.  It looks like the (yellow) Loop section markers, but it's  green and goes across the top of the timeline.  When you hover over the green bar, the cursor changes to something like <-S->, suggesting that you can drag the "S" section to do something useful.

What is it and what does it do? 

What keyword do I look for in the documentation?

(Ah! "Selection markers in time ruler")

Thanks!

 

 

Edited December 30, 2019 by dantarbill

[user 905133]