Separate Issue; Your System Details shows; Installed Plug-ins Adobe Shockwave for Director Netscape plug-in, version 12.0.6.147 Adobe Shockwave for Director Netscape plug-in, version 12.0.5.146 <br>Having more than one version of a program may cause issues. You must remove the older programs. Then get the current full installer. Flash: Grab the uninstaller from here: '''[http://helpx.adobe.com/flash-player/kb/uninstall-flash-player-windows.html Uninstall Flash Player | Windows]''' '''[http://helpx.adobe.com/flash-player/kb/uninstall-flash-player-mac-os.html Uninstall Flash Player | Mac]''' Then reinstall the latest version. Flash Player '''Version 18.0.0.160<br>https://www.adobe.com/products/flashplayer/distribution3.html''' Shockwave Director: [https://helpx.adobe.com/shockwave/kb/download-shockwave-stand-alone-installer.html Shockwave Standalone Installer / Uninstaller]{web link} Shockwave Director '''Version 12.1.8.158 http://get.adobe.com/shockwave/''' --------------------- Start '''[https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode Firefox in Safe Mode]''' {web Link} by holding down the '''<Shift><br> ''(Mac Options)'' ''' key, and then starting Firefox. Is the problem still there?

safe mode did not enable switch to tab. Thanks for the heads up about the plugin, though.

    History
    Bookmarks
[X] Open tabs

Make sure the Open Tabs has a checkmark. *Tools > Options > Privacy > Location Bar: When using the location bar, suggest: History Bookmarks [X] Open tabs