From support:

REALbasic makes this almost impossible. There is no frame type that RB supplies that does this — you have to create the window yourself using declares, because the window needs to have its WS_CHILD flag set to denote that it’s not a top-level window, but a child window owned by a parent. — Sep 18,2007

Bad, but at least the Windows coder at RS learned something about their lack of windows development skill. Their journey toward journeyman stature may have begun.