[ Thanks to Ian
MacGregor for this link. ]
“Stop-or-Reload Button
A button to stop loading the page or reload the page once it has
loaded. I feel that having separate buttons for the stop and reload
functions is a waste of space when there is a single button
available to support both functions.“Tab Mix Plus
Tab Mix Plus enhances Firefox’s tab browsing capabilities. It
includes such features as duplicating tabs, controlling tab focus,
tab clicking options, undo closed tabs and windows, plus much more.
It also includes a full-featured session manager.”