What slider? Please explain the purpose of the slider.

You have an overflow chevron at the right end side of the Bookmarks Toolbar to show bookmarks that do not fit in a drop down list.

It would be possible to give the various bookmarks drop down lists a scroll bar instead of the buttons that make the list scroll on hover.

Add code to the userChrome.css file below the default @namespace line.

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

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

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

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

#appmenu_bookmarks scrollbox,
#bookmarksMenuPopup scrollbox,
#bookmarks-menu-button scrollbox,
#PlacesChevronPopup scrollbox,
#PlacesToolbarItems scrollbox {overflow-y:auto!important}

#appmenu_bookmarks autorepeatbutton,
#bookmarksMenuPopup autorepeatbutton,
#bookmarks-menu-button autorepeatbutton,
#PlacesChevronPopup autorepeatbutton,
#PlacesToolbarItems autorepeatbutton {display:none!important}

I think to add the slider to list of bookmarks that is not visible. for example (image):

Try the code in the userChrome.css I posted above. That should add a scroll bar when there are enough bookmarks in the drop-down list. You can also consider to organize the bookmark a few folder to access them directly from the Bookmarks Toolbar.

There was an extension which added a scroll bar to the Bookmarks menu, but it shows that it is not available for Firefox 23. (https://addons.mozilla.org/en-us/fire.../bookmarks-scrollbar/)

In the following recent thread, cor-el posted an alternative approach: Why can't I scroll in the bookmarks drop-down menu? It used to scroll, now it doesn't.

@cor-el

In wich folder I must edit this, because I have 24 folders in "profiles"?

You need to create a chrome folder in the Firefox profile folder if this folder doesn't exist.

In that folder you can create a new file with the name userChrome.css and paste the above posted code in the file.
The name of the folder (chrome) and the file (userChrome.css) are both case sensitive.
Save the file as a plain text file without formatting code and make sure that "All files" is selected and not text file to prevent adding a possibly hidden .txt file extension that would give you userChrome.css.txt.

You can use this button to go to the Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)

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

Thank you! This work!

temporary solution:

1. download extension with other Browser https://addons.mozilla.org/en-us/firefox/addon/bookmarks-scrollbar/

2. download file is "bookmarks_scrollbar-1.1.0-fx.xpi"

3. open this file in winrar (don't check "Always use the selected program to open this kind of file"), don't close winrar

4. from it extract anywhere the file with the name "install.rdf"

5. now, delete this file "install.rdf" in winrar

6. open the extracted file "install.rdf" in Notepad++

6. find 11. row - "...maxVersion>3.0.*..."

7. replace it with - "...maxVersion>25.0.*..."

8. add modified extracted file in winrar (see step 3 under number)

9. now, open firefox and go to Tools-Add-ons and drag finaly file

10. install extension

11. restart

I found this with the help of https://addons.mozilla.org/en-US/firefox/addon/ft-evo/reviews/ post by AMINOMO (https://addons.mozilla.org/en-US/firefox/user/aminomo/)