Hacer que un formulario ocupe más de una pantalla

type 
   TForm1 = class(TForm)
   ...
    procedure WMWindowPosChanging(var AMessage: TWMWindowPosChanging); message WM_WINDOWPOSCHANGING;
    procedure WMGetMinMaxInfo(var AMessage : TWMGetMinMaxInfo); message WM_GETMINMAXINFO;
    procedure Button1Click(Sender: TObject);
   ...
  end; 
 
implementation 
 
procedure TForm1.WMGetMinMaxInfo(var AMessage: TWMGetMinMaxInfo);
var 
  _sz: TPoint;
begin 
 _sz := Point(3000, 2000);
 with AMessage.MinMaxInfo^ do begin 
  ptMaxSize := TPoint(_sz);
  ptMaxTrackSize := TPoint(_sz)
 end 
end; 
 
procedure TForm1.WMWindowPosChanging(var AMessage: TWMWindowPosChanging);
begin 
 // not inherited 
end; 
 
procedure TForm1.Button1Click(Sender: TObject);
begin 
 SetBounds(0, 0, 3000, 2000);
end;