Firefox windows have a title like almost all of other programs do, and they inherit their active tab's title. This normally isn't an issue, but it is an issue for private windows. There are many apps that will try to retrieve applications' titles. There's a chance that titles of Firefox windows are logged unintentionally. To get rid of this possibility private windows should not have titles inherited by active tabs. It should simply be 'Mozila Firefox' like when a 'new tab' is the active tab.