An interactive Beamline Matching application has been developed using beamline and automatic differentiation class libraries. Various freely available components were used; in particular, the user interface is based on FLTK, a C++ toolkit distributed under the terms of the GNU Public License (GPL). The result is an application that compiles without modifications under both X-Windows and Win32 and offers the the same look and feel under both operating environments. In this paper, we discuss some

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... of the practical issues that were confronted and the choices that were made. In particular, we discuss object-based event propagation mechanisms, multithreading, language mixing and persistence.