A workspieces problem has two parts, the workpiece and the operator. The operator is a person using a computer to control the workpiece. The workpiece is something inside the computer that changes only when the operator changes it. Some examples are a spreadsheet, UML diagram, or word processing document. The WorkpiecesFrame is ideal for object-oriented programming, and in fact classic object-oriented programming seems designed for it. Although object-oriented programming is used for all kinds of ProblemFrame s, it is most natural for this one. -RalphJohnson