This notification message is sent to the owner of a notebook control each time a tab's content is to be drawn by the owner of the notebook. The tab's content is drawn by the owner unless the owner sets the tab text or bit map by sending a BKM_SETTABTEXT or BKM_SETTABBITMAP message, respectively, to the notebook control.

param1
     USHORT      id          /*  Window identifier. */

param2
     POWNERITEM  powneritem  /*  Pointer to an OWNERITEM data structure. */