The form opens but the picture is not drawn

I try to make a drawing through the form, I made a code using DCL, the form itself opens, but the drawing does not appear. tell me please what i did wrong. 
I attach the code



(command "OPENDCL")
(defun c:Main ()
  (dcl_Project_Load "D:\Lb4" T)
  (dcl_Form_Show Lb4_Form1)
  (princ)
  )
(defun c:Lb4/Form1/TextButton1#OnClicked (/)
    (setq CoordX (atof(dcl-Control-GetText Lb4/Form1/TextBox1)))
    (setq CoordY (atof(dcl-Control-GetText Lb4/Form1/TextBox2)))
(setq d (atof(dcl-Control-GetText Lb4/Form1/TextBox3)))
(setq a (atof(dcl-Control-GetText Lb4/Form1/TextBox4)))
(setq b (atof(dcl-Control-GetText Lb4/Form1/TextBox5)))

(defun Lb4(d a b CoordX CoordY)

(setq StartPoint (list CoordX CoordY))

(command "circle" StartPoint (/ d 2))
 
(setq p1 (list (- 0 (/ a 2)) (- 0 (/ b 2)))
      p2 (list (/ a 2) (/ b 2)))
  (command "rectang" p1 p2)
  (dcl_messagebox (strcat "done"))
  (dcl_Form_Close Lb4_Form1)
)
)

Hello, the command will not work, until the form is open.
See https://opendcl.com/forum/index.php?topic=1080.0

With regards,
Fred