Count Bookmarks In Folders от kgersen

This extension adds a context menu item 'Bookmarks: a / b [x]' to bookmark folders menus.* These menus are opened when right clicking a bookmark folder in the Bookmarks Sidebar, Bookmarks Toolbar, Bookmarks Menu, and Bookmarks Library. This extension may be toggled off/on by clicking its toolbar button. When off, the bookmarks will not be counted.

* a: the total of all bookmarks that are immediate children of a bookmark folder.
* b: the total of all bookmarks inside a folder (including those within every subfolder).
* x: time in milliseconds to retrieve all the bookmarks so they can be counted.

The vast majority of Firefox users have less than 2000 bookmarks. Counting bookmarks for these users is a quick operation. However, for users that right click bookmark folders with large amounts of bookmarks, it may be a slow process. For example, it took around 1 second for the bookmarks.getSubTree method to finish on a bookmark folder with 50,000 bookmarks inside it that were spread among many subfolders. This number of course may differ one way or the other depending on a users CPU. For users that often open bookmark folder menus on folders with large amounts of bookmarks, it may be desirable to keep this extension off until actually needed so as not to waste extra CPU cycles.