
(*
 Delphi Object and Component Reference
# {bmc bm9.BMP} ClientHeight example
This example reduces the height of the form's client area by half when the user clicks the button on the form:
*) 
void __fastcall TForm1::Button1Click(TObject *Sender)
{
  Form1->ClientHeight = Form1->ClientHeight/2;
}

Note that only the client area is halved, not the entire form. 
