You need to right click the bookmarks toolbar and choose Customize. Then, you need to drag the 'Bookmarks Menu' button onto the Bookmarks toolbar and click 'Done'. This is different from the 'Library' button. Now when you click on it all of your Bookmarks folders will show up.

Note that you can also use the Bookmarks sidebar (Ctrl+B).

• https://support.mozilla.org/en-US/kb/use-firefox-sidebar-access-bookmarks-history-synced

There is also a Sidebar button in the Customize palette.

• https://support.mozilla.org/en-US/kb/customize-firefox-controls-buttons-and-toolbars

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