A few minutes ago Apple released the fifth developer preview of Xcode 4 to developers. It’s available in the Mac and iOS Dev Center. The release comes a month after the fourth developer preview.
This is a pre-release version of Xcode 4, a major new release of Xcode for both Mac and iOS development. This release requires Mac OS X 10.6 Snow Leopard, and includes the iOS SDK 4.2 GM seed, to develop apps for Mac, iPhone, and iPad.
As for this very specific build, new features for tabs, editors panes and alerts are introduced:
This preview introduces new features and enhancements for tabs, editor panes, and alerts. These features are designed to scale the single window interface of Xcode 4 to more effectively use available screen real estate, from the 11” MacBook Air, up to Macs equipped with multiple monitors. Please experiment with these new features to see how Xcode 4 can speed up your daily development tasks.