John Brant and Don Roberts divided the original refactoring browser into several components to aid in portability. They supported it on VisualWorks and VisualAge for a few years, so they had to separate the GUI from the engine, and to have a portability layer underneath. When it was ported to Squeak, someone wrote a new GUI and used pretty much everything else as-is. I tried using it, but the GUI seemed incomplete. The OB GIU is very solid.<br>
<br>-Ralph<br>