Double-arrow thing in the Timeline

mac OS Mojave 10.14.6

The double-arrow thing in the Timeline that you can adjust, & then playback just plays that section. Can someone point me to the section of the manual that covers it? I’m having trouble with it. I don’t want it there!

Thanks.

If you are referring to this:

then that indicates the current “play region” - that is, the region that is selected for playing.

In what way?

Some relevant sections of the manual:
https://manual.audacityteam.org/man/audacity_selection.html
and
https://manual.audacityteam.org/man/timeline.html#tqp