1. A method for rendering graphical objects on a display, the method comprising: rendering each of a plurality of graphical objects within respective layers, the plurality of graphical objects including first, second and third graphical objects, the second graphical object being directly linked to the first graphical object and the third graphical object being directly linked to the second graphical object; receiving user input manipulating one of the graphical objects in a manner that affects a directly linked graphical object; and re-rendering the manipulated graphical object and the directly linked graphical object without re-rendering graphical objects that are not directly linked to the manipulated graphical object.