Here's a way to add separators. Modify the browser.uiCustomization.state. In it is an array "placements"->"nav-bar". Inside that array, put the string "separator" (as many as you'd like) and restart Firefox.

Firefox only has flexible spaces available to be placed on the toolbar (they are placed at both sides of the location bar container).

Easiest to get a separator is to place a flexible space items in the correct position and then edit browser.uiCustomization.state to change the corresponding spring item to separator. Note that each ID needs to be unique, so using customization mode to drag a flexible space is the easiest way to achieve this. "customizableui-special-separator##" (separator) "customizableui-special-spacer##" (spacer) "customizableui-special-spring##" (spring)

Thank you. I would like the Firefox developers to note that separators visually separate elements while also being compact. I hope these separator elements remain in future releases.

Thanks for the tip. But why in the world aren't additional separators in the customization menu where they belong? Is there some technical reason for this or just a glaring oversight by the developers?

Hi giltheissen, I think the last version of Firefox with separators in the Customize panel might have been Firefox 28. If you were used to seeing that there in recent years, perhaps you were using the Classic Theme Restorer extension.

You're absolutely correct. I was using the classic theme addon. However what I find remarkable is that the developers gave me two draggable separators already in the toolbar when I initially downloaded firefox quantum. When I opened up the customize menu, I foolishly dragged them out of the toolbar into the customize menu, thinking I could drag them back in again when I figured out where I wanted them. Wrong move apparently since unlike every other button, these just disappeared never to appear again.

  So am I missing some logic behind this one-way drag to oblivion for the separators?

Hi giltheissen, when you refer to --

... the developers gave me two draggable separators already in the toolbar when I initially downloaded firefox quantum. When I opened up the customize menu, I foolishly dragged them out of the toolbar into the customize menu, thinking I could drag them back out again when I figured out where I wanted them.

-- were those the "flexible space" controls that center the address bar? You can add one of those from Customize, it looks like a blank rectangle.

Customize also has a Restore Defaults button if you want to go back to that initial layout and move things around without dragging them off.

Nope, I see the "flexible space" boxes. I dragged those out, too. These were two little separators, side by side. But unlike the flexible space buttons, these couldn't be dragged back up to the toolbar. Hence my confusion. But anyway, thanks for the "restore defaults" suggestion.

giltheissen said

Nope, I see the "flexible space" boxes. I dragged those out, too. These were two little separators, side by side. But unlike the flexible space buttons, these couldn't be dragged back up to the toolbar. Hence my confusion. But anyway, thanks for the "restore defaults" suggestion.

Open Customize and use Restore Defaults - that's how I got those two elusive "spaces" to return to the Navigation Toolbar.

This it the default value of browser.uiCustomization.state with the spring items:

{"placements":{"widget-overflow-fixed-list":[],"nav-bar":["back-button","forward-button","stop-reload-button","home-button","customizableui-special-spring1","urlbar-container","customizableui-special-spring2","downloads-button","library-button","sidebar-button","fxa-toolbar-menu-button"],"toolbar-menubar":["menubar-items"],"TabsToolbar":["tabbrowser-tabs","new-tab-button","alltabs-button"],"PersonalToolbar":["personal-bookmarks"]},"seen":["developer-button"],"dirtyAreaCache":["nav-bar"],"currentVersion":16,"newElementCount":2}

{"placements":{"widget-overflow-fixed-list":[],"nav-bar":["back-button","forward-button","stop-reload-button","home-button","customizableui-special-separator1","urlbar-container","customizableui-special-separator2","downloads-button","library-button","sidebar-button","fxa-toolbar-menu-button"],"toolbar-menubar":["menubar-items"],"TabsToolbar":["tabbrowser-tabs","new-tab-button","alltabs-button"],"PersonalToolbar":["personal-bookmarks"]},"seen":["developer-button"],"dirtyAreaCache":["nav-bar"],"currentVersion":16,"newElementCount":2}

You can do this with any separator you want to see on the toolbar (i.e first drag a spring to the toolbar, then edit browser.uiCustomization.state to change spring to separator, then close and restart Firefox).

You can open the about:config page via the location/address bar. You can accept the warning and click "I accept the risk!" to continue.

• http://kb.mozillazine.org/about:config