ParentWindow Property [Visio 2003 SDK Documentation]
Returns the Window object that is the parent of another Window object.
objRet = object.ParentWindow
objRet The parent Window object.
object Required. An expression that returns a Window object.
ParentWindow returns nothing and raises no exception if the window is a top-level window. A top-level window is a member of the Windows collection of an Application object.
Use the Parent property of a Window object to get the Windows collection to which a Window object belongs.