I have two forms. Form1 with richtextbox and form2 with listbox.

I'd like to put listbox on top of richtextbox, docking it. I want to do exactly like this:

Code:
form2.Controls.Remove(ListBox1)
form2.hide
form1.richtextbox1.controls.add(form2.listbox1)
form1.richtextbox1.hide 'I can't hide, also listbox will hide.. So let's do form1.controls.add(form2.listbox) instead.
form2.listbox1.location= richtextbox1.location or
form2.listbox1.bounds=richtextbox1.bounds
Everything works until setting form2.listbox1.location as If richtextbox1 is hidden also listbox will be. Also, setting location and/or bounds of listbox the same as richtextbox is not completely covering the richtextbox. I also tried using the same size for both.

I have tried also with:
Code:
Dim LB As ListBox = Form2.ListBox1
Form1.RichTextBox1.Controls.Add(LB)
LB.Location = New Point(0, 0)
LB.Size = Form1.RichTextBox1.Size
but if the text in the richtextbox is longer than the LB, then you'll still be able to scroll the RTB down to see that text.
Here a demonstration gif
So it is not really doing its job properly.. How can I make it ?
Thanks a lot!