Hi!
Congratulations, _ScreenToGif_ is AWESOME!
I have a suggestion for a new control for enable/disable loop playback.
It would be nice that at the right bottom corner.
Where the SelectFirstFrame/SelectPreviousFrame/Play/SelectNextFrame/SelectLastFrame are.
If enabled, would behave as it is now.
If disabled, the playback would stop at the last frame.
Best regards!
Something like this?

Thank you. :)
Also, it you didn't want to clutter up the lower toolbar, you could also just add a loop button/checkbox to the Playback tab.
Done, it will be available with v2.19.
Space is limited at the bottom of the editor, so I added to the ribbon.

Most helpful comment
Something like this?