I know the DWD concept never got off the ground since it was proposed ten years ago but it would be really useful to have decorations that can do the following:
- Display a menubar in the decoration/titlebar, together with a HUD, this basic concept from Unity should really be implemented regardless.
- Display individual menu items as separate buttons.
- Display custom buttons that invoke arbitrary “macros” (e.g. a button runs a user defined script relevant to the app). If KDE could automate mouse clicks based on images on the screen like Power Automate, then these custom buttons in the titlebar could be used to automate any GUI.
- Be flexible: they could be fat or thin, they could cut into the window chome up to a certain user-defined point to replace CSD window buttons with kwin window buttons. Like here, imagine if this is a CSD app with stupid CSD buttons, then the decoration masks them with SSD buttons. Or the application has a mostly empty menubar and you can save space by overlaying the titlebar on the menubar area. This would be a huge win for UI consistency and screen real estate.
- Embed arbitrary windows: thus you could group multiple windows into one, for example you could add a notes app as a sidebar to some other app, or embed a tiny monitor window into a stocks or communication app etc. Limitless possibilities there.
- Buttons and menus in the decoration should not interfere with dragging. Gnome CSDs are actually very draggable, more so than the current KDE titlebars actually (Kwin titlebars are skinny, you can’t drag from titlebar buttons, and they are by default blended in with the window chrome where dragging functionality is unpredictable - you think you’re dragging the titlebar but instead you end up dragging a toolbar etc, which is completely broken behavior.) Sorry but people worried about how putting additional buttons in the decoration is going to interfere with the window management are just wrong. On Gnome it’s actually EASIER than KDE, I can drag any window without even looking.
Note that none of this relies on implementing Kwin APIs within the apps themselves, which was the plan for DWD. A good idea but it was never going to happen. With this “power decorations” concept, a user or other third party can graft virtually any kind of additional functionality on top of any application, without the application ever knowing about it.
The same concepts can be extended to shortcuts and HUDs. Each app can get a custom set of keyboard shortcuts and a custom HUD to extend its functionality in arbitrary ways. KDE already does this with custom shortcuts actually, which you can set to run only when a particular app window is in focus.
Implementing this concept would be no simple matter, but once done it would be up to third parties to extend it however they want. If you ask me what’s the next big idea for the desktop metaphor, one that would actually be major step forward, this is the only thing I can tink of. After all, facilitating user interaction with applications is a core purpose of a “desktop environment,” right?