I used the GNOME extension at Gnome shell "show desktop" shortcut and now see too many desktop buttons. I think I might have tried to install it multiple times, apparently/maybe due to "nothing happening" each time I did so, until I realized later that it will not give any indication it actually installed something. Now I'm left with multiple "buttons" on the Panel next to the Activities navigation link:
This is under Ubuntu 17.10.
How do I remove all of them except for only one?
I do know about the ctrl+alt+d binding but I tend to disable the bindings in the settings, as I need to have all of the Ctrl and Alt key bindings reserved for specific application windows and not "gobbled up" by the X window manager.