You can improve it:
- Make our collection sharble and visible for the others.
- Add an otion to clean duplicate favs
- Sort the "Add to Coll" list in alphabetical order (as it was before)
- Make it Draggable (to see the video thumbnail hidden behind)
- In the popup, Clone the thumbnail of the fav concerned and Highlight it in the original favs thumbnail
- Put an indicator to each video fav , to show in how many collection it is
- Use a chek box at each favs, so we can add many favs in one or many collection(s) at once.