Unity Super + D shortcut doesn't work

There already is a keyboard shortcut that lets you see the desktop. It is just mapped to Ctrl + Alt + D. If you wish, you can remap it to Meta + D.

Search for Keyboard settings. Open Shortcuts tab. Move to Navigation. Scroll down until you see the option Hide all normal windows. Double click on it and press Meta + D. Now, Meta + D will show you the desktop from now on.

• What are the meta, super, and hyper keys?

Just got to settings ---> appearance ---> behavior ---> add show desktop to the launcher

then try the keyboard shortcut again

I went to Power Button > System Settings (Control Panel) > Keyboard Shortcuts and changed the shortcut key for the action "minimize all windows and set focus to desktop" to Super + D from Ctrl + Alt + D and now gedit obeys it too.

Its weird but its a bug that I certainly have no idea to reproduce. Another weird thing is I had to change it to Super + D & for some it works by default but since it seems to work fine now, I shall be marking this as the answer.