11. A method of operating a real-time validation tool embodied as software, the method comprising the steps of: extrapolating a timeline of an application as it is being built which provides interactive content that includes graphics to be rendered in a graphics plane when executing, the application comprising at least XML code, the timeline comprising an effect of the code on a system parameter over a lifetime of the application, the system parameter including pixel buffer usage; providing a user interface that is arranged for i) displaying the timeline and the pixel buffer usage and ii) displaying an editing window that displays the XML code, and iii) accepting edits to the code; and receiving edits from a user through the user interface to set one or more XPath queries in the code to true to enable evaluation of the effect on the system parameter as the application is being built.
11. A method of operating a real-time validation tool embodied as software, the method comprising the steps of: extrapolating a timeline of an application as it is being built which provides interactive content that includes graphics to be rendered in a graphics plane when executing, the application comprising at least XML code, the timeline comprising an effect of the code on a system parameter over a lifetime of the application, the system parameter including pixel buffer usage; providing a user interface that is arranged for i) displaying the timeline and the pixel buffer usage and ii) displaying an editing window that displays the XML code, and iii) accepting edits to the code; and receiving edits from a user through the user interface to set one or more XPath queries in the code to true to enable evaluation of the effect on the system parameter as the application is being built. 13. The method of claim 11 including a further step of indicating error conditions in the code through the user interface.