Hello 5cottie, bookmark separator is a visual separation between a group of icons, to remove the separator you must be in [https://support.mozilla.org/en-US/kb/customize-firefox-controls-buttons-and-toolbars#w_how-do-i-customize-or-rearrange-toolbar-items customize menu] see also : [https://support.mozilla.org/en-US/kb/customize-navigation-buttons-back-home-bookmarks#w_separating-or-spacing-the-toolbar-icons Separating or spacing the toolbar icons] thank you

You can remove separators on the Bookmarks Toolbar in the Bookmarks Manager (Library) in the Bookmarks Toolbar folder. *Bookmarks > Show All Bookmarks *https://support.mozilla.org/kb/Deleting+Bookmarks