Be careful with old versions!
These versions are displayed for reference and testing purposes. You should always use the latest version of an add-on.
[x] Fixed compatibility with future Firefox versions: don't use Array generics like `Array.forEach()` (bug 1222547).
[x] Correctly initialise sidebar in case of slow restoring of opened sidebar on startup (extensions.sidebarslist.ensureSidebarRestoredDelay preference).
[x] Fixed detection of full screen web applications in Firefox 41+ (#12).
[x] Hide useless second separator, if there is no third-party sidebar extensions.
[*] Updated icons for “Open Tab in Sidebar” and “Open Sidebar in Tab” menu items.
[*] Decode URLs in tooltip for “Open … in …” menu items (extensions.sidebarslist.decodeURIs preference).
[+] Right-double click on sidebar splitter/resizer to set alternative width (extensions.sidebarslist.sidebarWidthAlt preference).
[*] Simplified code around initialization.
[x] Fixed compatibility with Firefox 38+ (#10).
[*] Also show sidebar/page title (in addition to URL) in tooltip for “Open … in …” menu items.
[x] Correctly restore sidebar width limits on extension disabling/uninstalling.
[+] Added ability to zoom web page in sidebar (known limitation: doesn't work for Ctrl+mouse wheel) (#1).
[*] Don't use internal *.jar archive anymore (this should also improve performance on Firefox 4+).
[+] Added option to move tab to sidebar (hidden preferences: extensions.sidebarslist.openTabInSidebarClosesTab.useMove to preserve page state and extensions.sidebarslist.openTabInSidebarClosesTab.rightClickToInvert to invert move/open behavior using right-click) (#2).
[x] Correctly apply small splitter width on Linux (#3).
[*] Wrap built-in functions after small delay for better compatibility with other extensions (this also slightly improves startup performance).
[x] Correctly detect full screen mode in Firefox 3.6 and older.
[x] Correctly hide sidebar splitter, if active full screen web application (extensions.sidebarslist.splitterWidthFullScreenDOM preference) (#4).
[+] Added separate preference for splitter width in full screen mode (F11) (#5).
[x] Fix invalid `sidebarcommand` attribute to correctly close sidebar, if something went wrong (#6).
[*] Optimized: update splitter width and visibility only if needed.
[*] Hide previous contents in collapsed sidebar before opening of another sidebar (extensions.sidebarslist.collapseSidebar.clearBeforeSwitch preference).
[x] Correctly select first menu item, if sidebars menu was opened from keyboard (Ctrl+Shift+F4 by default) in Firefox 25+.
[+] Added: middle-click on sidebar resizer to close sidebar.
[x] Fixed compatibility with Sidebar Auto Show/Hide extension, if checked “collapse sidebar” option.