If you use the latest Chrome "Picture in picture" is available on youtube. Right click twice on the video to see the native context menu and there it should be.
But you should give myTube a try, which implements the much nicer native Windows 10 PiP.
It's the YouTube app. It's a mess. Get the myTube! app for Xbox from the Microsoft store. It's a free alternative to the official YouTube app. It doesn't have the jerky playback, it blocks the ads and it's just generally all-around better.
no prob. it's a UWP or whatever they're called these days so you can give it a spin on your computer while you wait for all those damn updates if your Xbox has been off for as long as I think it has
note: I got the IAP/unlock when it was on sale/free a long time ago, so I'm not sure how the base app compares.
Not really a solution on fixing it in Edge, but could always give third party apps a go for YouTube (mainly cause the website is just outright sluggish). I personally use My Tube! which allows popping out the player into a floating window and is pretty neat.
Sound keys (volume control, mute) are global, so when you push them, it bypasses everything else and tells Windows to mute everything,
This isn't a behaviour you can change, as far as I'm aware.
That said, media keys, like play/pause, stop, and skip, are global, but in a slightly different way, they control the current media application, whether that's Media Player Classic, Windows Media Player, VLC, Foobar2000, or whatever else you may use.
You MAY be able to use play/pause controls to pause youtube, but browser handling of media keys isn't quite as good as proper media player handling, so you may not be able to do anything about it without a dedicated program, THIS may work, but I'm unsure, I haven't tested it myself, and I'm not sure if it supports Youtube itself, or just Youtube Music.
This may also work, but I haven't tested it in this capacity. I will do so in a moment and edit once I know.
mytube! on Xbox has support for reading and posting comments. In a lot of ways, it's a far superior app than the official one and has been around for a long time.
APPX are unencrypted, so as long as the store link is still public you can download the APPX.
Go to microsoft.com/store
Search for the app you want to download APPX from (for example I'll use the link for MyTube!)
Link: https://www.microsoft.com/en-us/p/mytube/9wzdncrcwf3l?activetab=pivot:overviewtab
Go to here: https://store.rg-adguard.net/
Paste the link from Step 2
You'll see a bunch of generated links. You want the one that ends in .APPX and applies to your architecture. In this case for MyTube! you would choose "59750RYKENAPPS.435307C335C44_3.5.21.0_arm__zd92nzxdcatqw.appx"
If your using a PC get the MyTube app from the Windows store, it is an alternative front end for Youtube and it has none of the red of Youtube.
It has a faint progress bar and full screen with no logos.
The myTube app (.99 cents) supports 4K and I find it to be a solid app offering for less than a buck. Well supported as well and in active development.
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https://www.microsoft.com/en-us/p/mytube/9wzdncrcwf3l?activetab=pivot:overviewtab
if you use it for youtube, I recommend using MyTube, it is optimised for touch. It often becomes FREE, look out for the sale and you get to keep it.
Yes, it's an ongoing thing...there will never be a finished design, because the design itself is meant to evolve as they add more to it.
For 19H1, they added connected animation controls, and other depth effects.
Check out couple of apps with good use of Fluent Design, in addition to the built in windows 10 apps. MyTube and Notepadpro on MS Store.
https://www.microsoft.com/en-us/p/mytube/9wzdncrcwf3l
https://www.microsoft.com/en-us/p/notepadpro/9nbvtd6419f8
In Settings, personalization, colors, make sure Transparency effects are enabled.