To resolve my issue, I created a new user, moved my ~/.kde/ ~/.config/ and ~/.cache/ out of the way, copied over the ~newuser/.kde/ and ~/newuser/.config/, and reconfigured the desktop by hand.
I don't yet know what was the root cause of this issue, and I am willing to hand over my bad configuration file(s), to help resolve this issue. Just ping me at ubuntu.com(at)chenlevy.com.
To resolve my issue, I created a new user, moved my ~/.kde/ ~/.config/ and ~/.cache/ out of the way, copied over the ~newuser/.kde/ and ~/newuser/.config/, and reconfigured the desktop by hand.
I don't yet know what was the root cause of this issue, and I am willing to hand over my bad configuration file(s), to help resolve this issue. Just ping me at ubuntu. com(at) chenlevy. com.