I installed Diodon on my Xubuntu 18.04 using
sudo apt install diodon
Although Diodon does run (if I open the whisker menu and open Diodon I do see the clipboard menu), the icon does not appear on the taskbar.
As a plugin I do have application indicator checked.
I found a partial solution by creating a keyboard shortcut to launch Diodon (and show the menu), but I would also like to open the menu from the taskbar icon.
I did try right-clicking on the taskbar (or panel?), then "Add New Items" but I did not find Diodon there.
How might I resolve getting Diodon on the taskbar?