Firefox 4 will feature updated theme on Windows, Mac OS X, and Linux. The following changes can be expected in the Windows version: » Firefox button (called Minefield) gathers most frequently used menu options in a single point. The button is on by default for Windows Vista and 7, but off for XP » Aero Glass interface. a new skin that fits with default Vista and Windows 7 themes » Customizable tab bar. ability to drag buttons to the tab bar » bookmarks button. opens up bookmarks menu and options to show the bookmarks menu and bookmarks sidebar. » Tabs on top are now enabled by default. To restore the classic layout with the navigation toolbar above the tab bar, right click on the navigation toolbar and uncheck Tabs on top.