Hi cproud, you can restore the gray heading Recently Bookmarked and following five bookmarks using one of these methods:

(1) Context Menu

Right-click (or on Mac maybe Ctrl+click) an entry near the top of the bookmarks menu and choose Show Recently Bookmarked from the bottom of the right-click context menu

Note: On Mac, you need to do this on the bookmarks menu that drops from the toolbar button shown in the following image, it doesn't work on the Bookmarks Menu that drops from the main menu bar.

(2) Directly Edit a Preference

The menu item switches a hidden preference between true to false, and you can do that directly as follows:

(A) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful.

(B) In the search box above the list, type or paste book and pause while the list is filtered

(C) Double-click the browser.bookmarks.showRecentlyBookmarked preference to switch the value from true to false or false to true, as the case may be

Success?

It didn't help because when I opened Bookmarks today, suddenly there was Recently Bookmarked, near the top of the list (not in its original location). Good enough, and all my recently bookmarked selections were there. I will hang on to your suggestions, however, in case this happens again.

Now, why isn't there the old choice 'Bookmark this page' there as well?

Mozilla, it's fine if you want to offer things you think are improvements, but please don't force them on us. I was quite happy with things the way I was used to them.

cproud said

Now, why isn't there the old choice 'Bookmark this page' there as well?

Isn't where? It should be on the Bookmarks menu on the menu bar, it is not on the menu displayed by the toolbar button.

I just noticed that in your original post, your Firefox identified itself as version 48. The "Recently Bookmarked" section of the menu was added in Firefox 49, and the current version is Firefox 50. I wonder whether your Firefox recently rolled back for a day somehow?? That would be very odd.

Thanks for your comments. Seems this is another victim of having OS Mountain Lion OS 8.5 on my Mac Book Pro. This OS no longer supported by Firefox. They say I would have to upgrade my OS to even get Firefox 49. But you say the Recently Bookmarked feature was part of 49, so I don't know how I ever had it???? Of course you will suggest, upgrade immediately to a higher OS such as the (not too much longer) latest El Capitan. Well, that is a whole other story; for several reasons I don't want to update my OS; updating has caused havoc with some of my files and software in the past and I don't want to deal with that. Want to wait until I get a new computer, which is not going to happen for a while. And it won't be a Mac! Macs are fine if you want frequent OS changes (why?) and like all the new bells and whistles. I don't (nor do I care for Apple Arrogance). I'm retired and have few demands on my computer except to work as it always did. I don't have need or desire for latest software features. Sigh. And the computer powers that be will not let that happen.

Hmm, maybe I misunderstood what you had. Firefox 49 introduced a new section to the menu as pictured in the attached screenshot. There was always a blue "smart folder" called Recently Bookmarked either on the bookmarks menu or on the bookmarks toolbar. If that folder disappeared, it could have moved to a different location or it might need to be regenerated.

Versions of Firefox you can run

Please see this article: Firefox support has ended for Mac OS X 10.6, 10.7 and 10.8

Finding a lost/misplaced bookmark folder

The Library dialog ("Show All Bookmarks") has a search box, but it doesn't search for folder names. Instead, you can export your whole bookmark hierarchy out to an HTML document (web page) and open that in a Firefox tab to search for it. This article has the steps to create that document: Export Firefox bookmarks to an HTML file to back up or transfer bookmarks.

If you locate it in the document, you can check the Library dialog for that location and move it back where you want it.

Regenerating deleted smart folders

If the folder isn't misplaced and needs to be re-created, please see Restore the default Smart Bookmarks Folders.