I create a comm object and event handler in form init()

When the form is closed by clicking upper right corner, event handler Destroy()
event does not fire. Why ?

* Form Init()
this.oComm = createobject( "mscommlib.MSComm" )
EVENTHANDLER( this.oComm, NEWOBJECT("commevents", 'pump.prg' ) )

* File pump.prg contains:

DEFINE CLASS commevents AS custom
IMPLEMENTS DMSCommEvents IN "mscommlib.MSComm"

procedure Destroy
* this event does not fire when form is closed. why ?
ENDPROC

PROCEDURE DMSCommEvents_OnComm() AS VOID;
HELPSTRING "Occurs whenever the value of the CommEvent property changes."
ENDPROC
ENDDEFINE