• "Most Visited" and "Recently Bookmarked" and "Recent Tags" are examples of so called Smart Bookmarks folders and are not real existing folders.
• Such smart folders show a list created by a query of the places.sqlite database that stores the bookmarks and the history in Firefox.
• Smart folder lists show a maximum of 10 entries by default.
• Bookmarks or history items that show up in a smart folder list are stored elsewhere in another folder and any changes made are applied to the real bookmark or history item.

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

Name: Recent Tags
Location: place:type=6&sort=14&maxResults=50

How do I edit the query???

Try this code in the userChrome.css file below the default @namespace line.

• http://kb.mozillazine.org/userChrome.css

The customization files userChrome.css (interface) and userContent.css (websites) are located in the chrome folder in the user profile folder.

• http://kb.mozillazine.org/Editing_configuration

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* only needed once */

#editBMPanel_locationRow, #editBMPanel_keywordRow {
 visibility:visible!important;
 -moz-box-align:center!important;
}