Could you add the following features:
1) **an option to save the various options selected.** So that we can easily import these chosen saved options back again whenever we want.

2) **Add a stop button** to stop the video at its very start. Sometimes it is useful to check again what was the original starting image of the video. Or when you want to repeat from the very start.

3) In the theater mode, there is an extremely annoying "More videos" option that appears and it is impossible to see below this "More videos" option the comments.
I could very well be a BUG.
Add **an option to get rid completely of this "More videos" option in this theater mode and replace it by allowing instead to be able to see the comments normally** instead of this very annoying "More videos" set of video links.
---Remark: Strangely, this problem seems specific to Firefox because it does not appear when using Microsoft Edge with this same addon improve youtube.

4) Below the description, there is now (sometimes but not always) a summary section that is created automatically. **Allow us to chose, for this summary section, the option expanded** like it is available also for the Description.

---One issue:
**Under the section Player, Pause while I watch a 2nd video.** It does not work if you watch a 2nd video that is a short video; in such a case, the first video will NOT pause while the second short video will keep running and the sound of the first video will interfere with the sound of the second short video!
It does not work even for any video that you watch first! Very annoying.
This is a serious BUG.

Thanks to the developer for this addon.