Actually the IFM does not really care what kind of user interface you use. Motif/Athena support was in the dialogs, but we have - for example - widely used MFC (e.g., for IfmMIKE11) and Qt. For Qt, however, you would have to make sure that the plug-in uses the same Qt version that is used for FEFLOW - this makes modules with Qt user interfaces somewhat more difficult to maintain over longer time periods.