The mystery of the vanishing menus
Mozilla's collapsed the usual menus under the single button at the far left, dubbed "Firefox." You can't miss it ... it's burnt umber and prominent. But only Windows Vista and Windows 7 get the Firefox button in the first beta. Compare this button with what Chrome uses, below.
The "stable" build of Chrome uses a pair of buttons at the upper right to hide traditional menus, but as a Computerworld reader pointed out, Google just moved to a single button in the "dev" channel for Windows. Cross-pollination, baby!