1. A performance data editing method for a computer system containing a display, comprising the steps of: controlling the computer system to display a plurality of layers on a screen of the display, wherein at least one execution icon corresponding to execution-related data can be attached to each of the layers; providing an instruction to control at least one of the layers to be placed in a display mode or a non-display mode selectively; and controlling the computer system to perform or stop displaying the at least one of the layers in response to the instruction.