A method for operating a data processing system having a touch enabled display screen that displays a plurality of waveforms to alter the display of one of the waveforms without altering the display of the remaining waveforms is disclosed. The method includes determining a selected waveform in response to a user touching the display screen in a first location thereby defining a touch area that determines the selected waveform. An operation that is to be performed on the selected waveform is then defined by a gesture on the screen. The selected waveform is determined by a touch area that is defined by the user touching the screen. If more than one waveform is defined by the touch area, the possible waveforms are sequentially selected until the correct one is presented to the user in response to the user repeating the touching that defines the touch area.