Support for Picture-in-Picture windows
Picture-in-Picture is a feature that allows watching videos in a floating window. On desktop, web browsers such as Firefox provide support for this feature.
A picture-in-picture window is almost the same as a normal window except a few minor bits:
- It is placed above other windows. On X11, it is achieved by setting the _NET_WM_STATE_ABOVE state
- It is not listed in the task manager. On X11, it is achieved by setting the _NET_WM_STATE_SKIP_TASKBAR state
Currently, it's unclear how picture-in-picture mode can be properly implemented on Wayland as there is no way to instruct the compositor that a window should not be listed in the task manager and be placed above other windows.