IS_PORTAL are mutually exclusive.</DD>
<DT>
VTF_IS_PORTAL</DT><DD>
This flag is set if the object is a portal. A portal is an object that has its own window and appears in its parent's window. A portal differs from a window (VTF_IS_WINDOW) in that the window has no part of itself drawn in its parent window. This flag implies that the VTF_IS_COMPOSITE flag must also be set indicating the object may have visible children. All visible children of a portal will appear in the portal's associated window if VTF_CH