Tip to enable YouTube video Picture-in-Picture(PiP) mode on Mac's Safari like Arc/Zen
Option 1
1. right click speaker icon in the address bar
2. select Enter Picture in Picture
Option 2
1. double - right click on the video
2. select Enter Picture in Picture
Tip to customize Mac's Safari like Arc/Zen
1. disabled Always Show Toolbar in Full Screen ( View > Always Show Toolbar in Full Screen )
2. show or hide Vertical tab ( Command + Shift + L )
3. copy current URL ( Command + L and Command + C )
I think @Apple@AppleSupport should give up solution for this error. My Macbook pro 13" 2016 non touch bar and 13" 2017 with touch bar got same issue can't do my work.
https://t.co/SFVzxIPMXr