I'VE BEEN VERY LAX IN TERMINOLOGY. SORRY.
No, the rest are fine. 18 plus FOLDERS containing Bookmarks. Because the folders fill the toolbar, all overflow is accessed via the double arrow under the hamburger.
It is a FOLDER I called Bookmarks that has gone missing, with many items. When that Folder is popped down, the first items were in a box. "Bookmark this (current whatever)" When I'd bookmarked the item, that wording at the top of the folder changed
by itself to Edit this Bookmark etc., It was very handy and used every day for as long as I can remember.
The thing is, I didn't build that specialist item in the Bookmark folder. The wanted items were in boxes before getting to the long list of Bookmarks which I don't use.
In other words, Firefox must have designed that pop-down. No right clicking, and instantly reachable. And gone. 
It happens that I send everything to the toolbar and it overflows into the pop-down under the double arrows. I do this because dragging from there can be fast and to the literal point.
Now that I've managed to lose Histories from the main library of symbols I know that I must spend more time on keeping up with the system. While attempting this, I've lost a paper on some of the complexities of outer electrons in complex atoms. It was a good paper. And gone.
I too have been using Firefox for decades. However, I've been very aware lately that I've just slumped at my PC and done only what interests me at the moment and not kept up with maintenance. I was very keen once. I know this computer is not up to much - to get more memory would mean throwing the existing 4gb away. I'd guess that's why I got the Motherboard and Chip for a song. I'd rather thought this PC would last me out.
Indeed, a friend has been caught out, a very late i7 and endless RAM and it still doesn't qualify for W11. I didn't want to be messed around like that.
I'm going to start a new thread on Ccleaner. What's happened is very unpleasant as I can only assume their actions are deliberately obstructive. Hoards of complaints substantiate my concerns. I've supported and promoted Ccleaner since they started, and it's scant reward.