If you open the sample "Acme" project, you can get a feel for how DialogBlocks works by navigating through the project. There are several top-level elements, including dialogs, a frame, and an application object. The latter generates the wxApp-derived class that is necessary for a wxWidgets application to compile and run. It's not essential to have this element in DialogBlocks if you are writing your application class by hand and are just using DialogBlocks to create visual elements.