Hello, i found this idea on the internet:

Go to about:config and change this option Browser.urlbar.default.behavior to 1

• about:config
• Browser.urlbar.default.behavior

It is currently set to 1, so the gui preferences seem to be setting about:config flags correctly...

Also, if I set it to suggest nothing, or only bookbarks, those both work fine. In my instance, there just isn't a difference between 'history and bookmarks' and just 'history.'

Any other ideas?

I'm running v26 on OSX Mavericks.

Is the problem in the drop-down list (yellow star shows with entries), or in the "autofill" suggestion in the address bar itself?

Does it occur in Firefox's Safe Mode as well? That's a standard diagnostic tool to bypass interference by extensions (and some custom settings). More info: Diagnose Firefox issues using Troubleshoot Mode.

You can restart Firefox in Safe Mode using

Help > Restart with Add-ons Disabled

In the dialog, click "Start in Safe Mode" (not Reset)

Any difference?

Did you verify that you haven't visited those bookmarked pages causing them to become history items?

You can check for problems with the places.sqlite database file in the Firefox profile folder.

• http://kb.mozillazine.org/Bookmarks_history_and_toolbar_buttons_not_working_-_Firefox
• https://support.mozilla.org/kb/Bookmarks+not+saved#w_fix-the-bookmarks-file