Hi, Please try '''Restore Default Set''' in the '''Customize...''' window. If it's still not visible, one reason could be that the button is already placed on the toolbar but may be hidden behind another icon or toolbar. ............................................................................................................................... Useful links: [https://support.mozilla.com/en-US/kb/Options%20window All about Tools > Options] [http://kb.mozillazine.org/About:config Going beyond Tools > Options - about:config] [http://kb.mozillazine.org/About:config_entries about:config Entries] [https://support.mozilla.com/en-US/kb/Page%20Info%20window Page Info] Tools (Alt + T) > Page Info, Right-click > View Page Info [https://support.mozilla.com/en-US/kb/Keyboard%20shortcuts Keyboard Shortcuts] [https://support.mozilla.com/en-US/kb/Viewing%20video%20in%20Firefox%20without%20a%20plugin Viewing Video without Plugins] [http://kb.mozillazine.org/Profile_folder_-_Firefox Firefox Profile Folder & Files] [https://developer.mozilla.org/en/Command_Line_Options#Browser Firefox Commands] [https://support.mozilla.com/en-US/kb/Basic%20Troubleshooting Basic Troubleshooting] [https://support.mozilla.com/en-US/kb/common-questions-after-upgrading-firefox-36 After Upgrading] [https://support.mozilla.com/en-US/kb/Safe%20Mode Safe Mode] [http://kb.mozillazine.org/Problematic_extensions Problematic Extensions] [https://support.mozilla.com/en-US/kb/Troubleshooting%20extensions%20and%20themes Troubleshooting Extensions and Themes] [https://support.mozilla.com/en-US/kb/Troubleshooting%20plugins Troubleshooting Plugins] [http://kb.mozillazine.org/Testing_plugins Testing Plugins]

Vivek, Have already tried the 'Restore Default Set' that did not reveal the 'open new tab' button in the 'Customize Toolbar' menu. Also, with 'Customize....' open, have moved all navigation bar items around and that did not reveal the missing button. So, still searching for an answer. ps.

Possibly corrupt localstore.rdf ([http://kb.mozillazine.org/Corrupt_localstore.rdf Corrupt localstore.rdf] ) read '''cor-el''' '''solution chosen''' '''and ''replys''''' here: https://support.mozilla.org/de/questions/801457 [https://addons.mozilla.org/en-us/firefox/addon/new-tab-toolbar-button/ New tab toolbar button - add-on] thank you

OK, deleted the 'localstore.pfd' file, but initially this did not correct to problem because the 'open new tab' button was not visible on the 'Customize Toolbar' menu. BUT, per suggestion above from Vivek when in 'Customize....' I really dug around under several toolbars, and that button became visible when the 'List all tabs' button was moved. So, not sure which solution worked, but problem is corrected. Thanks to both of you, ps.