8. The computer program product of claim 7 , where in causing the computer to retrieve the main program from the memory, the computer readable program code when executed on the computer causes the computer to: retrieve at least one layer file associated with the main program from the memory; display program code corresponding to the at least one layer file and the main program; and where the computer readable program code when executed on the computer further causes the computer to: determine whether to hide the program code corresponding to at least one of the at least one layer file in response to a detected user input from a user; and where in causing the computer to initiate the layer representing the portion of the main program for editing on the display, the computer readable program code when executed on the computer causes the computer to initiate the layer based upon the determination of whether to hide the program code corresponding to the at least one of the at least one layer file.
11. The computer program product of claim 8 , where in causing the computer to display the program code corresponding to the at least one layer file and the main program, the computer readable program code when executed on the computer causes the computer to: display the program code corresponding to the at least one layer file and the main program in a program code displaying region; and display descriptive information corresponding to the at least one layer file in a layer management region.