1. A computer-readable medium having computer-executable components for implementing tabbed browsing, the components comprising: a tab window manager component; a plurality of tab window components, each configured to manage communication between the tab window manager component and an individual tab out of a plurality of tabs, the plurality of tab window components having a one-to-one relationship with a plurality of content windows and each content window being associated with one of the plurality of tabs, each content window having its own heterogeneous content and being processed by its own thread; a tab user interface component configured to render a user interface for the plurality of tabs, the user interface providing a content-specific menu based on the heterogeneous content in the content window; and a browser frame component configured to broker communications between the tab window manager component and the tab user interface component.