add or remove icon from taskbar/top panel ubuntu 16.04
When right-clicked on any icon in the top panel in GNOME fallback mode, it will show only “Launch” and “properties” options.
To add or remove application launchers / icon in the gnome-panel you need to do the following.
Press Windows key (one with the windows symbol) + Alt key simultaneously and right-click the top menu bar.
It will show the options to add/remove icons and panels.
To remove an icon from there, press the key combination and click on the icon.