You should be able to cancel the page loading with the ESC (Escape) key on the keyboard. Current Firefox versions use a combined Stop/Reload/Go button that is positioned at the right end of the location bar. *During the page load process it shows as a Stop button and after the loading has finished the button is changed to a Reload button. *If you type in the location bar then that button becomes a Go button. *Middle-click or hold the Ctrl key and left-click the Reload button to duplicate the current tab to a new tab.