Ctrl-Super-D fails as well. Ctrl-Alt-D works and is listed in the shortcut overview that can be summoned by holding Super. However, in the overvies it says "Ctrl-Alt-D == Minimizes all windows", which might be semantically different. And anyway, what I gathered from the comments is that Super-D should work; not sure if I read that correctly.
Ctrl-Super-D fails as well. Ctrl-Alt-D works and is listed in the shortcut overview that can be summoned by holding Super. However, in the overvies it says "Ctrl-Alt-D == Minimizes all windows", which might be semantically different. And anyway, what I gathered from the comments is that Super-D should work; not sure if I read that correctly.