INT 15 - TopView - SEND MESSAGE - "DIR" - GET PANEL FILE DIRECTORY
        AH = 12h
        BX = 0300h
        STACK: DWORD handle of panel object
Return: STACK: DWORD length of directory (always multiple of 14 bytes)
               DWORD address of directory
Note:   a null string is returned if the object is not open
SeeAlso: AH=12h/BH=83h

Format of panel file:
Offset  Size    Description
 00h  2 BYTEs   C0h C3h
 02h    BYTE    number of panels in file
 03h    for each panel in file:
            8 BYTEs  blank-padded panel name
              DWORD  panel offset in file
              WORD   panel length
        data for panels (each consists of one or more window/query/manager
        streams)
            first byte of each panel must be 1Bh, fifth byte must be E5h