Set browser.startup.page to 0, to prevent Home Page to be opened
If your Firefox/Iceweasel is set to open the Home Page (or old tabs) at startup, it opens the Home Page as well when opening a new window.
I think this is a privacy issue, since the Home Page could tell a lot about someone - depending on the Home Page. To prevent this from happening torbutton would only need to set browser.startup.page to value "0" while activated and restore the old value afterwards.
Trac:
Username: erikesterer