CopyQ Not Pasting in Ubuntu 18.04 (Gnome 3.28.2)

I love CopyQ, but now I have some problems with it. I recently upgraded from Ubuntu 16.04 to Ubuntu 18.04. With this, I started using Gnome 3. After the upgrade, CopyQ wouldn't start or run at all, so I completely uninstalled and removed all CopyQ packages, then started fresh according to your docs.

Now it's installed and partially functional, but not working as it was prior to the OS upgrade. The clipboard fills the CopyQ list and the items are there, but when I click them (with my mouse) to fill in fields (whether in the web browser -- Firefox 71.0 -- or on my system), the data doesn't fill in. I can click an item with the mouse, then use Ctrl-V to paste (apparently that puts it into the clipboard), but this defeats the whole purpose for me. I fill in lots of fields routinely with the same information. Or I might need to copy, say, 10-15 items all at once, then sequentially add them to a message or set of forms, one by one. Going back and forth between two applications, pressing Ctrl-C and Ctrl-V, respectively, is super annoying; this is whole reason I started using CopyQ in the first place.