I recently went to add the scroll to bottom bookmark for Safari on my first generation iPad. After creating and saving the shortcut on the Bookmarks Bar, my new “button” suddenly disappeared. At this point, I realised I had forgotten to turn on the Always Show Bookmarks Bar switch in settings.
This setting is easy to find – if you remember it – open the Settings application, scroll on the left until you see Safari and then tap this option. Toggle the Always Show Bookmarks Bar setting to the ON position.