Windows only. Whether the dialog is embedded inside the parent window or has a window of its own.
YES or NO. If the value is YES, the dialog will appear embedded inside its parent window (you must set a parent, either with PARENTDIALOG or NATIVEPARENT, or this setting will be ignored). If the value is NO, the dialog will have its own window.
This is useful for implementing ActiveX controls, with the help of the LuaCOM library. ActiveX controls run embedded inside another window. LuaCOM will send a window creation event the the control, passing a handle to the parent window and the size of the control. You can use this to set the dialog's NATIVEPARENT and RASTERSIZE attributes. See the LuaCOM documentation for more information.
IupDialog