1. A method for displaying relevant portions of Register Transfer Language source code corresponding to displayed waveforms of signals, the method comprising the steps of: a. displaying a plurality of waveforms of signals in a graphical user interface window; b. inputting a user request to display portions of Register Transfer Language source code that correspond to the value of a signal or transition in the value of a signal at a particular time; c. identifying the portions of the Register Transfer Language source code corresponding to the user's request; and d. displaying the identified portions of the Register Transfer Language source code.