Form.Release + NIL

Question

if Form.Release is called after using the form, it will free all related memory but not set the form variable to nil.

if not assigned (Form1) then
  begin
    Ap         


        

Answer 1

Put the line

  Form1 := nil;  

just after the call to Release.

Release is just posting a CM_RELEASE message to the Form which allows the Form to finish what's in its queue (event handlers) before handling the CM_RELEASE message which means normally just calling Free.
So, after calling Release, you should not assume that the Form variable still points to a valid Form, thus putting nil into the variable.