X11's separation of policy and mechanism was a mistake. Maybe it made sense at the time - I don't know. GUIs were new at the time. Now that we know how they're supposed to work, the flag should really be called "I am a window manager" rather than "root window substructure redirect", and "I am a special window" (e.g. combobox drop-down) rather than "ignore substructure redirect" for example. (Even better, define some kind of window class flag so the window manager CAN see it and knows it's a combo box drop-down).
> and "I am a special window" (e.g. combobox drop-down) rather than "ignore substructure redirect" for example. (Even better, define some kind of window class flag so the window manager CAN see it and knows it's a combo box drop-down).
I think X11 has had that for a very long time. In the late 2000s when Beryl was still separate from Compiz, it was almost trivial to target things like dropdowns by a descriptive name and give them different effects than regular windows. Mine had an accordion effect while windows would burn up.
My point is that X is in the right direction more than Wayland is, in the spirit of its design, and major pain points of X are largely due to its specific design/implementation. Perhaps an outgrowth of having a lot of tiny policy-mechanism components is lack of standardization, which did strike X, but I think that's an orthogonal concern and not better served by overly large, inflexible components.
