Displaying Window Center In Oracle Forms10g at run time

Center  a Window Automatically in Oracle Forms 10g at Runtime by this Process

# CREATE A PROCEDURE center-form IN THE program units LIKE-

PROCEDURE CENTER_FORM(MyWindowName IN varchar2,UpperMargin IN number) IS
    x number(6);
    y number(6);
BEGIN
    SET_WINDOW_PROPERTY(FORMS_MDI_WINDOW,TITLE,'ORACLE');
    Set_window_property(forms_mdi_window,window_state,maximize);
    x:=((get_window_property(forms_mdi_window,width)-get_window_property(MyWindowName ,width))/2);
    y:=((get_window_property(forms_mdi_window,height)-get_window_property(MyWindowName ,height))/2+UpperMargin);
    set_window_property(MyWindowName , position,x,y);
END;

# FORMS-LEVEL-TRIGGER:

  Trigger Name:
  When-New-Form-Instance:
  Declare
  timer_id   Timer ;    
  Begin    
  timer_id := Create_Timer( 'delay', 50, NO_REPEAT ) ;
  End ; 

  Trigger Name:
  When-Timer-Expired:
  CENTER_FORM('WINDOW1',0);