so I think the proper solution is the one I linked to so that all skins automatically get this.
Except it's not, that won't work. This kind of thing can't be implemented directly in Media Center like it can in other apps, simply because Media Center uses custom skins and not native OS UI elements, menus, buttons, etc. Because of that the
only way to do this with Media Center is through the skins themselves. Media Center (like other apps like Steam and Adobe Photoshop) are not typical Windows (or Mac or Linux) apps and they don't use the "expected" Windows (or Mac or Linux) UI elements, menus or even the buttons for that matter. In both Media Center's and Steam's cases they use custom skins either bundled with the apps itself or created by third-parties which have to usually be added manually. For argument's sake let's say that
if JRiver added support for Windows 11's rounded corners in Media Center, how would that even work? I'm not aware of any part of Media Center that uses the native OS UI elements like window frames or menus. Regardless if some sort of support was added to the main app, it's still all in vain since all the skins would still need to be modified to add the rounded corners, so adding support for rounded corners any other way is pointless. Thus, things like rounded corners has to be done through the skins and not the app itself.
Like I said in the first post Media Center uses its own system for window drawing, menus and everything else, which means supporting stuff like this wouldn't be easy to do (and again, pointless due to skins). Keep in mind Media Center doesn't even use the minimize/maximize/restore/close buttons from the OS/system UI, it's all from the skins too. Skins
can support what you're wanting, either you have to create a skin and add rounded corners to the images or you can fork and modify the existing skins and add rounded corners to the images that way. Basic image editing skills is recommended! But, that reminds me...
Here's a sneak peek of what I've been working on, a work-in-progress of the new Modern Cards Acrylic Dark Edition skin with rounded corners and rounded menus to better fit the Windows 11 aesthetic...
And here's another sneak peak, the work-in-progress version of the new Modern Cards Acrylic Light Edition skin with rounded corners and rounded menus to better fit the Windows 11 aesthetic...
And finally, another sneak peak of the near final version of the new Modern Cards Acrylic Grey Edition skin with rounded corners and rounded menus to better fit the Windows 11 aesthetic...
This is probably as good as it's going to get for a "Windows 11" skin with rounded corners and menus.