Although the private browsing feature in Firefox works just fine, it leads to a disruptive experience because of its global design. A per-window approach is a much more comfortable because you no longer give up your regular session from the get-go.
It took about 19 months of work for this feature to reach a Firefox Nightly build, and it required complete rewriting of the private browsing mode.
The new private browsing mode opens up in a window separate from the regular session. You can also open a link straight into a private session from the right click menu, as the “Open Link in New Private Window” option has been added.
In the case of Google Chrome, Internet Explorer and Opera all private sessions are started in a separate instance of the application. Opera goes even further with the feature and offers the possibility to open private tabs in the same session.
Check out the images in the gallery below for a look at the new feature.