Like any other browser Opera has many options to let it be configured precisely to your likings. This is done through the usual interface as well as through a configuration page just like Firefox' about:config. A great deal of options
If you like being lazy and want to browse sites you don't have in your bookmarks already in the fastest possible way, there is a Firefox option that lets you determine what happens with expressions entered into the url bar.
From version 4 on, FireFox has disabled the option to save tabs when you leave the browser and left us with the Restore Session option on program start. To enable the option to save tabs again, direct FireFox to about:config
Apart from the wide variety of plugins available for Mozilla Firefox and the option to configure it in the Preferences window, there is another, slightly more hidden feature to customize Firefox' behavior . To access it, enter about:config into your