1. A computer program product, tangibly embodied in an information carrier, the computer program product comprising instructions operable to cause data processing apparatus to perform operations comprising: detecting multiple changes to a user interface of a computer program, the user interface having multiple user interface elements, each change being a change to one of the multiple user interface elements; generating a rendering request for each change, each rendering request specifying the user interface element that has changed and a type of modification to be performed on the user interface element; and filtering the requests to eliminate redundant requests.