As of 2019/06/24, this addon works as it is intended with the latest version of Firefox (67), both for HTML 5 and flash players.

To the developer.
Improvements that I would like to suggest to the developer and I hope they should be easy to implement.
1) Just allow the button to be used as a toggle button without having to open a small window and select either N or repeat.
2) When the user decides to stop the repeat function by selecting N, allow the current video to finish to its end and not stop it right away after you select N to stop the repeat.

With these 2 improvements, this addon will become perfect I believe, something that is very rare.

One remark. AVG Free antivirus targets your addon as a possible security threat. Is it accurate, I do not know at all.

Many thanks to the developer Mark for this addon, highly appreciated.

amazing! Thank you a lot! flawless and simple.

Ok