This is a feature "Picture in Picture".
App can play the video in a pop-up window floating video popup video above other applications.

Using:
- In YouTube App choose to share on YouTube PiP for playing.
- Support move pinch and zoom video. You can set Fullscreen or Collapse.
- Support play local video in background the same as play music mp3.

*** You can watch YouTube videos while chatting playing games work your love it's great !!!