One embodiment of the present invention provides a system that enables a user interface manager to modify a scene graph for an application. During operation, the system receives the scene graph for the application, wherein the scene graph defines visual attributes for a user interface associated with application. Next, the system uses the scene graph to render a visual output for the user interface, and displays the visual output to a user of the application. The system also enables the user interface manager to modify the scene graph, whereby the user interface manager can produce visual effects for the user interface in addition to visual effects produced by the application.