I upgraded from v2.4
in v3.1, “Enable Quick-Play” no longer appears as an option under the green triangle drop-down menu at the left edge of the timeline.
Can anyone point me to documentation on how to regain the functionality of “Quick-Play” in v3.1?
I have visited the online documentation for v3.1and it does show a screen capture of the menu with “Enable Quck-Play” present…
However, this option does not appear in my installation of v 3.1…
The current version of Audacity is 3.1.1 (available here: https://www.audacityteam.org/download/)
Normal (not “looped”) Quick Play is always enabled (can no longer be turned off).
Playing loops has changed with a new “loop” mode, which is documented here: https://manual.audacityteam.org/man/tutorial_looping.html
Good catch robcat 
I have added a P1 to the alpha manual for the upcoming 3.1.3 release to update that image, so the the person who now edits and uopdates the manual will see that.
From 3.1.0 onwards with new looping you will find that Quick-Play is always enabled, you can no longer disable it.
Peter.