I found an unofficial source for that extension and it seems that the entire menu is reduced to one line for some reason. It's very hard at this point to research the changes between Firefox 31 and 32 to figure out why; maybe someone already did the analysis and posted it?

As an alternative to the extension, would you consider using a custom style rule? For example:

• https://userstyles.org/styles/81419/column-bookmarks (also at https://gist.github.com/sogoo/4644583)

There isn't a sample screen shot, but I tested it and it does show two columns for my quantity of bookmarks. BUT! The items are distributed left right left right, rather than having a second column continuing from the first, so if you like alphabetical order, it will be somewhat disorienting to use...

Nope, two columns, not in column order is (to be polite) Sub-Optimal. Request Fire Fox developers either provide a new version, compatible with 'Multicolumn Bookmarks 1.5' or provide multi-column navigable Favorites view as a program option.

This is only support, we pretty much work with what is available today. You can submit requests in one or more of the following places to see whether you can recruit some assistance:

(1) Feature in a future version of Firefox:

https://input.mozilla.org/feedback

(2) An extension:

https://discourse.mozilla-community.org/c/add-ons

(3) A custom style rule:

https://forum.userstyles.org/categories/style-requests

Those are in order of slowest to fastest development time, but also in order of decreasing power to modify Firefox.

Thanks, I will submit a 'Fix It' request.

Here's a custom style rule: https://userstyles.org/styles/119797/bookmarks-menu-in-multiple-columns

I attempted to instal Stylish as directed, but this resulted a connection error. See screen capture.

Try installing from the official page directly: https://addons.mozilla.org/firefox/addon/stylish/

Sorry, to complete the thought:

(1) Install Stylish from the Mozilla Add-ons site

https://addons.mozilla.org/firefox/addon/stylish/

(2) Then return to the user style page to get the style (the button should be green instead of blue at that point)

https://userstyles.org/styles/119797/bookmarks-menu-in-multiple-columns

Hey, That worked! I've updated to the current version, and Firefox show a three column navigable favorites display!!

Thank you for your assistance!!!

Sincerely,

Arnold Stone