Synced Bookmarks are not showing up in Bookmarks Dropdown Menu
I am setting up an new computer and after installing Firefox on the new computer, I synced Firefox with my old computer. The bookmarks from my old computer show up in the Library under "Manage Bookmarks," but they are not showing up in my Bookmarks Dropdown menu. For the life of me, I cannot figure out how to display them in my dropdown menu.
Opaite Mbohovái (1)
The "Recent Bookmarks" list that shows in the second screenshot shows the results of a database query sorted by date added and isn't a real folder. What it shows in this recent list are bookmarks stored in other folders. In the Library in the right panel you see a list of bookmarks and folders of the folder selected in the left panel, in your first screenshot the Bookmarks Menu folder.
You can drag the Bookmarks Menu button that shows the bookmarks in a drop-down list from the Customize palette to the Navigation Toolbar. This Bookmarks Menu button has a "View bookmarks sidebar" menu item.
See "How do I add the Bookmarks Menu button to the toolbar?"