Want some very cool Firefox trick? Just enter the codes below on your Firefox address bar and just hit enter. chrome://browser/content/browser.xul – Opens another Firefox inside a tab in the the existing Firefox window. chrome://browser/content/preferences/preferences.xul -  Opens the Options dialog box inside the Firefox tab. chrome://browser/content/bookmarks/bookmarksPanel.xul -  Opens the “Bookmarks Manager” inside a tab in [...]