The Adobe Express View Engine (EVE) is the recommended method of laying out UI widgets in InDesign dialogs. The main benefit of using EVE is that widget geometry is calculated for you, so that when you add or remove widgets to a dialog all of the other widgets are shifted automatically without you having to recalculate sizes etc.
InDesign user-interface development can be expensive. It takes a lot of effort to implement a dialog or panel in ODFRC. Things should improve in future versions, with the possibility of using Flash-based user-interface tools like Flex and FlexBuilder. While this represents the future direction of InDesign user-interface development, there is a present reality in InDesign CS4. With an understanding of the current situation, you can implement Flash-based user-interfaces for InDesign CS4.