Various other operating systems offer a Picture-in-Picture effect, and I was under the impression that we didn't--but in fact we have one too! It's the "Thumbnail Aside" effect, which is off by default. It just needs some love to make it competitive and discoverable. Proposals:
- Rename to "Picture-in-Picture" (that's what it's called everywhere else)
- Improve default settings: 100% opacity and ≥300px wide
- When activated, allow the PIP window to be moved, resized, and closed with the mouse
- When the effect is enabled, make it discoverable by automatically adding a window decoration button to window titlebars that will activate the effect for that window when clicked
- Enable it by default (after all other changes are made)
With those changes, I think KWin's PIP effect could compete with the best of them. :)
Then, the promo team could promote the heck out of it so that people don't have the impression that we're lacking this feature anymore.