how to change default number tags shown in drop down

You will only see a maximum of 10 items in such a smart query list.

• "Most Visited" and "Recently Bookmarked" and "Recent Tags" are examples of so called Smart Bookmarks folders and are not real existing folders.
• Smart folders show a list created by a query of the places.sqlite database that stores bookmarks and history in Firefox.
• Smart folder lists show a maximum of 10 entries by default.

• https://developer.mozilla.org/Places_query_URIs

You can possibly create a new place query bookmark and adjust the maxResults parameter.

Name: Recent Tags
Location: place:type=6&sort=14&maxResults=10

so there is no easy way to display more than 10 "smart bookmarks" which makes them pretty dumb. It makes half my recent tags unavailable and the one I use most is now at number 11 which forces me to use my history folder. Making a query bookmark isnt that simple as just having a spot in the About:config section to change the max number of recent tags, very frustrating. Thanks anyway, but I had already seen that solution.

You can create a bookmark and leave out the maxResults to see all recent tags

• place:type=6&sort=14

Although I appreciate your help, this is just another work around and doesn't address the issue. Why allow me to have more than 10 tag categories if I cant see them. I don't need another work around, what I was hoping for was somewhere in the about:config there would be a value that could be changed so that I can see more than 10 tag categories.

Did you try to create a new bookmark with the above posted place:type=6&sort=14 place query and replace the current Recent Tags bookmark?

That should show you all present tags.