It would be nice to create a seamless experience for our users between an application that uses the RadFileDialogs and their native Windows OS. To that end, having the RadFileDialogs use the same InitialSelectedLayout as the base OS would go a long way. Adding some way to identify the current Windows setting and to set the RadFileDialog accordingly would be a great help.
When designing architecture of the dialogs, our main priority was to be absolutely consistent with the Microsoft dialogs, not only functional but also visual. The Microsoft dialogs initial layout has not synchronized with the initial one of the Explorer. For that reason, and for the reason that we exposed such kind of property, I will recommend you to get the current view of the Explorer with the IFolderView::GetCurrentViewMode method and set our InitialSelectedLayout property to the needed value.