User-Agent: Mozilla/5.0 (Windows; Windows NT 6.1; WOW64; en-US; rv:2.0b2pre) Gecko/20100704 Minefield/4.0b2pre Build Identifier: Mozilla/5.0 (Windows; Windows NT 6.1; WOW64; en-US; rv:2.0b2pre) Gecko/20100704 Minefield/4.0b2pre Correct me if I'm wrong, but it seems the tabs are not going to be moved up to the titlebar, to keep the space open for dragging of the window. If this is the case, the titlebar should show the title of the open tab again, because as of now the titlebar is a lot of wasted space. Having the title in the titlebar is useful if many tabs are open, as the textfield in the tab shrinks. Reproducible: Always