Embodiments described herein are directed to simultaneously displaying proxy windows for application windows and/or tabs included in such application windows via a graphical user interface of an operating system. For instance, an application programming interface (API) associated with an application that supports a tabbed document interface (TDI) provides information associated with each tab opened within an application window associated with the application. An API of the operating system receives and utilizes such information to generate and display a proxy window for each tab. The proxy windows for the tabs may be displayed alongside proxy windows of application windows for other applications. The proxy windows may be generated and displayed in response to user invocation of various features of the operating system graphical user interface, including, but not limited to, a task switcher feature, a taskbar feature, or a window snap feature.