anchor.diff:  
     TGoForm = class(TForm)
     private
  -    FAllowDropFiles: Boolean;
       FOnDropFiles: TDropFilesEvent;
       FOnStyleChanged: TNotifyEvent;
       FOnWndProc: TWndProcEvent;
  +    FAllowDropFiles: Boolean;
       procedure SetAllowDropFiles(const Value: Boolean);
       procedure WMDropFiles(var Msg: TWMDropFiles); message WM_DROPFILES;
       procedure CMStyleChanged(var Msg: TMessage); message CM_STYLECHANGED;
  +    function GetAllowDropFiles: Boolean;
     protected
       procedure InitializeNewForm; override;
     public
       constructor Create(AOwner: TComponent); override;
       procedure WndProc(var AMsg: TMessage); override;
     published
  -    property AllowDropFiles: Boolean read FAllowDropFiles write SetAllowDropFiles;
  +    property AllowDropFiles: Boolean read GetAllowDropFiles write SetAllowDropFiles;
       property OnDropFiles: TDropFilesEvent read FOnDropFiles write FOnDropFiles;
       property OnStyleChanged: TNotifyEvent read FOnStyleChanged write FOnStyleChanged;
       property OnWndProc: TWndProcEvent read FOnWndProc write FOnWndProc;
  
positive.code: 
  procedure TGoForm.SetAllowDropFiles(const Value: Boolean);
  begin
    if FAllowDropFiles <> Value then
    begin
      FAllowDropFiles := Value;
      DragAcceptFiles(Handle, Value);
    end;
  end;
  
  procedure TGoForm.WMDropFiles(var Msg: TWMDropFiles);
  
negative.code: procedure TGoForm.CMStyleChanged(var Msg: TMessage);
  begin
    inherited;
    // ޸ʽɵ⣬ϷţʵʴڷѾˣ
    // á
    if FAllowDropFiles and not AllowDropFiles then
      AllowDropFiles := True;
    if Assigned(FOnStyleChanged) then
      FOnStyleChanged(Self);
  end;
  