2 Pane Bookmarks
Ver.1.0.2016020701 for Mozilla Firefox
This provides separated "Bookmarks" Sidebar panel like Opera. This splits the Bookmarks Sidebar panel with 2 panes. When you choose a folder from the above tree, the contents will be shown in the below pane.
There is the updating history and the list of known problems.
Works on Nightly 47.0a1.
Drop support for Firefox 37 and older.
Modified: "jar" archive is no longer included.
Fixed: Make codes E4X-free, to work lately versions of Firefox.
Works on Minefield 4.0b10pre.
Drop support for Firefox 3.0.
Fixed: Bookmarks tree was broken when you drag and drop bookmarks in the sidebar.
Works on Minefield 3.7a5pre.
The option "open bookmarks in new tab always" has gone. You should use
Open Bookmarks in New Tab instead. Fixed: Lower pane is correctly shown even if you click twisties just after you show the bookmarks sidebar.
Fixed: Works correctly for "Unsorted Bookmarks" and other special folders.
Fixed: The title of the selected folder is correctly restored after the bookmarks sidebar is opened again.
Works on Shiretoko 3.1b3pre.
Drop support for Firefox 2 and older.
Improved: Height of panes are saved and restored.
Fixed: "Only one folder open" mode works correctly on Firefox 3.
Fixed: Errors on selecting folders disappeared.
Works on Firefox 3.0 beta5.
Added: Italian locale is available.
Fixed: The credit of hu-HU translator is corrected.
Added: Hungarian locale is available. (by Mikes Kaszm???n Istv???n)
Fixed: Separators disappear from the folder pane.
Fixed: Drag-and-drop actions on splitted tree work correctly.
Improved: One of trees will be hidden automatically when you start to find bookmarks.
Improved: The content of the last selected folder is shown when the bookmak sidebar is loaded.
Improved: The root folder is available in the upper pane.
Improved: The selected subtree is not collapsed automatically if it is already expanded.
Improved: Firefox 2 is supported. (maybe)
Fixed: Slovak language pack is updated.
Added: Slovak language pack (sk-SK) is available. (made by Jacen)
Fixed: Duplicated tabs opened from the below pane disappeared.