...
  private 
    { Private declarations } 
  public 
    procedure WMPosChange(var Message: TWMWINDOWPOSCHANGING); 
      message WM_WINDOWPOSCHANGING; 
  end; 
 
var 
  Form1: TForm1; 
 
implementation 
 
{$R *.dfm} 
 
procedure Tform1.WMPosChange(var Message: TWMWINDOWPOSCHANGING); 
begin 
  PWindowPos(TMessage(Message).lParam).Flags := 
    PWindowPos(TMessage(Message).lParam).Flags or 
    SWP_NOMOVE or SWP_NOSIZE; 
end;