Customizable bladed applications

Customizable bladed applications are described herein. A device platform is configured to provide a simultask mode that enables combined user access to multiple applications of the platform via respective chrome portions. When simultask mode is active, arrangement of chrome elements within a user interface is controlled to generate a bladed view that provides a compact representation for one application in conjunction with an expanded view that provides principal chrome for a different application. The platform makes the bladed view available for any displayable application of the platform. The bladed view may also include application-specific elements that are populated using customizations designated via metadata of the application, or using default information for applications in the absence of designated customizations. Further, the platform may implement a notification system that operates on behalf of applications to obtain and apply updates for dynamically updatable content incorporated into bladed views.