A dynamic disposing of userControl

[Atara]

I have a control on a userControl1 on a userControl2 on a userControl3
on a Panel on a Form and sometimes I cannot close my form.

I understand it is a known bug that was already discussed, but I
cannot adjust the following solution to my case:
- In which class do I add the following code? (who is 'this')
- Do I have to do it for both userControl1, userControl2 and
userControl3 or just for userControl1 ?

Any help is wellcomed.

Atara.

--------------------
The code I found:

Subject: Why hasn't this .NET bug been corrected yet?

problem:

when a control within a UserControl has focus and is then disposed,
the top-level form containing that disposed control will fail to close
when the 'X' is clicked or when Close() is called.

solution:

if(panelUserControlHost.Controls.Count > 0)
{
if(this.ctlActiveUserControl != null)
{
panelUserControlHost.Controls.Remove(this.ctlActiv eUserControl);
this.OnControlRemoved(new
ControlEventArgs(ctlActiveUserControl));

ctlActiveUserControl.Dispose();
ctlActiveUserControl = null;
}
panelUserControlHost.Controls.Clear();
}