MDI : creating child windows with child windows

In my MDI app I create the child forms at runtime (just like borland
tells you to)
But now I have a problem.... I open a form called something like 'edit
products' then in that form you can click a button to 'edit the prizes'
of a product.

So from the mainform you go to a child form and with that child form I
want to create a new child form.

The problem is that the child form with whom I create the new child form
is destroyed
after the new Child form appears on the screen. This is not what I want.

I want the two child both on the screen.

Notice : the new child window just has to be a child of the main form so
we just call
TMDIchildNew.Create(Mainform);

Can anyone help me ???

thanks in advance.