Aw, fsck. When I restored from hibernation this morning, things didn't look so good. The panel that works as a dock has gone the other way from the condition it's been lately. Instead of squeezing everything into a tiny square, it now displays full-size, but showing only the two left icons.
Strangely enough, when I clicked on the location where my Terminology icon used to display (far right), Terminology is what started, so I was able to get things started there.
So, I clicked where Vivaldi should be, but just got the tired old error message about "No internet..." At that point, I did the screencap you see above, getting Spectacle from the menu instead of the dock. Also, the hibernation problem that I thought was solved by changing Vivaldi's setting to save a week of browsing data instead of the 3 months it defaulted to was back.
C'mon KDE. 222 packages updated, and this is what I get? Gonna try one more reboot, and see if it sorts itself out once more.
EDIT: I did a full shutdown instead of a reboot, as I wanted to make sure I didn't leave any debris anywhere. Here's the dock now, so I'm hopeful that things are once again working as they should. So far, so good.
Next, I'll populate the workspaces in the upper panel, and do a brief hibernation, to see if the Internet is still connected when the laptop wakes up. I suspect it will be fine.