1. To select a link text hold the Alt key and select it.
2. To open search results in a new tab press Alt+Enter in the search bar.
3. To open new tab from the Run window or Command Line for a custom profile:
firefox -p [prof-name] -new-tab http://google.com
4. If you are closing a tab by mouse wheel and get a dialog “This page is asking you to confirm that you want to leave” then press the wheel again to close the tab completely.