Add Bookmark Here ² has a larger dialog window so you can see more folders. And you can make that section of the dialog larger, to suit your needs.
https://addons.mozilla.org/en-US/firefox/addon/3880
The third image on that page shows you how to 'drag' the panels larger.

Are all those folders made as sub folders of the Bookmarks Menu folder of the Bookmarks Toolbar folder?

See also:

• Use bookmark folders to organize your bookmarks

bookmarks menu

this add-on didn't help my tool bar doesn't show Mozilla Firefox

Bookmarks placed in the Bookmarks Menu folder only display in the Bookmarks Menu and in the Bookmarks sidebar. If you want to see them on the Bookmarks Toolbar then you need to move them to that folder.

If that isn't what you mean then try to explain better and if possible attach a screenshot.

below is a image of my save bookmarks opens on my PC windows 7