Dynamic Object Linking
**********************

Overview
========

   Usually, the complete user interface of an application is created
with one single command. This makes error handling very easy and allows
parallel usage of several windows. However, sometimes it makes sense to
create certain windows only when they are actually needed: For example,
if an application supplies many subwindows and would use too much
memory, or if the number and contents of needed windows is not known at
application startup time.

   Therefore MUI supports the option of "late binding".  Using this
mechanism, children can be added and removed after their parent object
already has been created. MUI uses the methods `OM_ADDMEMBER' and
`OM_REMMEMBER' for this purpose:

     DoMethod(parent,OM_ADDMEMBER,child); /* add child object    */
     DoMethod(parent,OM_REMMEMBER,child); /* remove child object */

   Both methods are only supported by MUI's application and group
class; these are the only classes that can manage several children.
Dynamic object linking for window and group class is explained in
detail in the following chapters.

   Note: Objects that do not have parents, be it, because they are not
yet connected using `OM_ADDMEMBER' or because they were disconnected
using `OM_REMMEMBER', it's the programmer's task to delete them by
calling `MUI_DisposeObject()'.  On the other side, objects that still
are children of other objects must not be deleted!