Mozilla Firefox - Windows - Linux

    When I click on "the star" - Bookmark this page, top right in the Address Bar, tags field missing. 

The tags field is missing from bookmarks editor.

SOLUTION:

1.    Launch Firefox. You must have at least one tab open.

2.    Right-click on the tab. From the drop-down menu, select "Bookmarks Tab..." .

3.    In the new window, select "Tags" and enter a randomly selected word or a number. This will enable the missing "Tags" field. Press "Save".

4.    Press "Ctrl + D". You now have a "Tags" field in bookmarks editor.

    That is all.