It would be better if the parameters under user control could be typed directly into the text boxes that display them. The current system brings up new windows with dialog boxes to enter cart parameters whenever the "create your own" button is selected. This tends to create a lot of windows; especially since the only way to remove these windows is to click the "done" buttom in the body.
Finally, alpha is changed by clicking a button within the applet; however, this button is only active when the "create your own" option is selected. When it is active, the dialog window pops up behind the applet. These peculuarities make the applet somewhat awkward to use.