PROPERTY FUNCTIONS

 A property list is a storage area that contains handles for data that the 
 application needs to associate with a window. 

 Once a data handle is in a window's property list, any application that can
 access the window can also access the handle. Using the property list is a
 convenient way to make data (for example, an alternate title or menu for a
 window) available when the application needs to modify a window. 

 Every window( and control! ) has its own property list. When a window is
 created, the list is empty. The SetProp function adds entries to the list
 Each entry contains a unique Windows character string and a data handle
 The data handle can identify any object that the application needs to
 associate with the window. The GetProp function retrieves the data handle
 of an entry from the list without removing the entry. The handle can then
 be used to retrieve or use the data. The RemoveProp function removes an
 entry from the list when it is no longer needed. 

 Although the purpose of the property list is to associate data with a window
 for use by the application that owns the window, the handles in a property
 list are accessible to any application that has access to the window. This
 means an application can retrieve and use a data handle from the property
 list of a window created by another application.