Author: Tomas Rutkauskas 

If you want to give your users the ability to move your application by dragging it
by clicking anywhere on your application window (see Windows 3.1's Clock 
application),
here's what you can do:

1   private
2   
3   procedure WMNCHitTest(var Msg: TWMNCHitTest);
4     message wm_NCHitTest;
5   
6   ..
7   
8   procedure TForm1.WMNCHitTest(var Msg: TWMNCHitTest);
9   begin
10    inherited;
11    if htClient = Msg.Result then
12      Msg.Result := htCaption;
13  end;