This is a screen capture of what I'm talking about.

It is possible to place other items on the Bookmarks Toolbar and the position to the right of the chevron suggest that this has happened in this case.

Use Toolbar Layout (Customize) to open the Customize window and set which toolbar items to display.

• Firefox menu button > Options
• View > Toolbars (press F10 to display the menu bar)
• Right-click empty toolbar area

You can try to drag this item that should appear next to the "Bookmarks Toolbar items" off the Bookmarks Toolbar into the toolbar palette.

• https://support.mozilla.org/kb/How+to+customize+the+toolbar

If that isn't possible then check your extensions.

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

You can also check for problems caused by a corrupted localstore.rdf file.

• http://kb.mozillazine.org/Corrupt_localstore.rdf

Hey James,

I tried what cor-el suggested, and I found the problem to be the Zoom Page add-on for me: disabled it, and the box went away. I was unable to remove the box using the first method cor-el suggested. This issue popped up for me today as well, and I've had Zoom Page installed for at least a few months, so I don't know what the deal is. Hopefully you have the same add-on installed, cheers!

punjab, you're solution was exactly right. I disabled the Zoom Page add-on, rebooted my browser, and the problem went away. So either Zoom Page had a buggy update, or it was not compatible with a FF update.

I had the same problem and disabling Zoom Page worked. If anyone finds out that Zoom Page has an update that fixes this, please let us know so that we can re-enable it!

Did you try to update the extension?

It seems that there has been a Zoom Page 9.1 version released.

• https://addons.mozilla.org/firefox/addon/zoom-page/

Yes, I was running Zoom Page 9.1. It had the problem.

Are you sure that you have the 9.1 version, because in 9.1 this section is commented out (it is present in 9.0)?

• view-source:chrome://zoompage/content/zoompage-browser-overlay-4.0.xul

    <toolbar id="PersonalToolbar">
<!--
        <toolbaritem id="zoompage-debug-info" class="chromeclass-toolbar-additional" style="width: 400px; margin: 3px 5px 2px; padding: 0px 5px; border: 1px solid #C0C0C0;"/>
-->
    </toolbar>

Well, I have 9.1 now, re-enabled it, and it looks like the box is gone. So, maybe it auto-updated while disabled?

Yes, it doesn't matter whether an extension is enabled or disabled in respect of checking for updates.
Firefox will check for updates in both cases and install them automatically if that is the default for the extension.

Thanks. I think it's fixed.