UPDATE for PC - I actually had firefox ver 39.0 on my PC . I updated to ver 40.0. It is confirmed that activating/deactivating OLDBOOKMARK behavior prevents/enables me to bookmark single sites.

This extension? https://addons.mozilla.org/en-US/firefox/addon/old-add-bookmark-behavior/

There were a few minor changes in 40 with regards to bookmarks; mainly with the keywords API being replaced. Maybe that extension got broken as a result of a change?

I routinely save the same bookmark to different folders, but never saw the point of using an extension to restore the lost functionality when Firefox 3.0 was first released. I just drag'n'drop a bookmark into a folder to save it, and do it again to save the same bookmark into another folder. Still works in Firefox 40 for me - just verified it still works.

Drag'n'drop works best to the Bookmarks Toolbar or into the Bookmarks Sidebar. No longer works well when trying to open "Bookmarks" on the Menu Bar and no longer works when trying to use the combined "Bookmark this page" / "Show your bookmarks" button pair - the folders no longer open as they once did.

thats a good trick and I can use it sometime, but I am not really able to use it all the time. Sometime I can save to a folder if it is visible in the tool bar. But I have lots of folders and some are not visible so I like the ability to have a drop down menu of folders that I can place my bookmark in. Also it seems like there is some extra "moving around" as I have a big screen and I have to "fly around " alot with my cursor. By the way, yes, that is the extension I am talking about.

Well, if that extension quit working for you see the support page for it over here. http://forums.mozillazine.org/viewtopic.php?f=48&t=795945&start=30

Now that I read some postings in that thread, it looks like it has breaking one piece at a time for a number of years now.

IM just turning the extension off and try your method from now on.

Note that you can also use copy and paste in the Bookmarks Manager (Library) and in the bookmarks sidebar to make a copy of a bookmark elsewhere. I assume that on Mac you can drag the tab on to the combined Bookmarks Menu button (star) on the Navigation Toolbar to bookmark the current tab in a folder of your choice. If you hover either of these buttons then the drop-down list should open.

yeah the drag and drop seems good thanks

Can you no longer choose "Bookmark This Page" from the Bookmarks menu? Did they remove that as well as all the other stuff they removed? What about the star? Does double-clicking that no longer work?

finitarry , right, if I click "bookmark this page" , I see the item in the menu bar flash, but nothing gets saved, and same if I do CTL-D , to bookmark single sites. Clicking the star appears to work (the star moves) but no bookmarks get saved.

If you either click "Bookmark This Page" or double-click the star, you no longer get a dialog box popping up?