INT 15 - DESQview v2.42-2.52 - BUG
        AH = 12h
        BH = 17h
        BL = object
            00h DWORD on top of stack
                mailbox, keyboard, or pointer only
            02h mailbox for task whose handle is on top of stack
            03h mailbox for current task
            04h keyboard for task whose handle is on top of stack
            05h keyboard for current task
Notes:  due to a fencepost error, message 17h is accepted for mailboxes,
          keyboards, and pointers, but causes a random branch
        DESQview v2.50-2.52 are distributed as part of DESQview/X v1.02