Firefox has added some new features to Private Browsing: stakes around the approach.

Firefox progressively continues to stuff its browser with new features to help users manage more or less efficiency their private life or data. In the latest version of Firefox, henceforth you can open a new private window without closing or interrupting your current browsing session.
This means that the Private Browsing
gives you control of your personal data by letting you browse the Web without saving any information about which sites and pages you've visited. ‘’For example: If you're shopping for a present, you don't want Firefox to ruin the surprise by keeping a list of all the pages you were shopping on. ‘’
This lastest version is available Here  to download !