The present invention is directed to a system and method for providing a score window containing various types of execution icon layers onto which execution icons are attached and arranged in conformity with a progression of a musical tune on a screen of the display. In accordance with the preferred embodiment, each layer is controlled in response to various display commands. The system allows a user to select desired execution icons from an icon select palette that provides lists of execution icons which are registered in advance. Specifically, the user may select and "drag" an execution icon from the palette and place it at a position in correspondence with a particular point of progression of the music to be edited, causing the editing function corresponding to the execution icon to be effected at the point of progression of the musical piece. In accordance with the preferred embodiment, the execution icons are displayed by categories in accordance with a category display layer, which may be controlled to be displayed or not displayed in the editing screen.