I changed my mind about the user interface. I'll use a more scalable interface, which will be different from ResEdit's. I'm making it so that there is only one depth visible at the same time (you can switch between them by using a pop-up menu). Then I have enough room to display all the sizes, and the number of items that I choose to display can be flexible (so that theoretically I could add an option to turn off the displaying/editing of huge and mini icons, since they're not used very often). I've done a mockup in RealBasic, and all I have to do now is implement it using CodeWarrior.