There’s a longstanding bug report to get window shading working on KWin Wayland.
I’m wondering why couldn’t this feature be implemented as setting the height of a window to 1px and its contents have a 0% opacity.
But I’ve never looked at the KWin Wayland code so I don’t really know why shading seems to be a hard feature to implement.
Here is an example of window shading if you have not heard of it. It’s a far more efficient way to manage unused windows than a task bar
According to the mailing list the problem is that resizing the window would cause all sorts of issues for Wayland and applications running in it and a heavy load on the system. However, I’ve always seen shading as hiding the window rather than resizing it. I find it hard to believe it’s not possible to minimise a window while leaving its titlebar visible or creating a placeholder titlebar for display on screen while the window is hidden.
Shading is something I really miss. Like the cube, it’s one of those useful cosmetic effects which distinguishes Plasma from other desktop systems and enables more efficient desktop and window management when working.