Here's a version that seems to work well. I moved your preset frame over next to the destination frame. I also reorganized the buttons a little.

This version now creates a visible instance variable for the application.

#MatCloneApp(Tkinter.Tk(), '').master.mainloop()<br></br>matcloneapp = MatCloneApp(Tkinter.Tk(), '')<br></br><br></br>matcloneapp.addpreset( 'v3 body skin', ('SkinTorso','SkinNeck','SkinArm','SkinHand') )<br></br>matcloneapp.addpreset( 'v3 skin head', ('SkinHead','SkinScalp') )<br></br><br></br>matcloneapp.master.mainloop()

Notice the new class method addpreset().
This has the added effect that you can run another python script (while this one is running) that looks like this.

# Posette Bits preset<br></br>try:<br></br>  matcloneapp.addpreset( 'posette bits', ('nostril','lips') )<br></br>except:<br></br>  pass<br></br># comment line, so we don't end the script on an indented line.

and this preset will be added to the preset listbox.
This seems pretty flexible.