User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:74.0) Gecko/20100101 Firefox/74.0

Steps to reproduce:

1. Have multiple youtube videos playing in different tabs
2. Click on the Picture-in-Picture button for each videos

Actual results:

1. The opening Picture-in-Picture on the second video closes the first Picture-in-Picture pop out and opens a new one with the second video

Expected results:

Two Picture-in-Picture pop out should appear, each playing their own video.

This has been reported on reddit:

1. https://www.reddit.com/r/firefox/comments/espdua/how_to_have_multiple_pictureinpicture/
2. https://www.reddit.com/r/firefox/comments/ffczhl/use_multiple_pictureinpicutre_popouts/
3. https://www.reddit.com/r/firefox/comments/eyhvmw/any_way_to_use_multiple_pictureinpicture_mode/

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

Thanks for the report Nils, it seems this is a duplicate of bug #1589680.