anchor.diff:      function    DoWindowToScreen(ASource: TfpgWindowBase; const AScreenPos: TPoint): TPoint; virtual; abstract;
       procedure   DoSetWindowTitle(const ATitle: string); virtual; abstract;
       procedure   DoSetMouseCursor; virtual; abstract;
  +    procedure   DoEnableDrops(const AValue: boolean); virtual; abstract;
       procedure   SetParent(const AValue: TfpgWindowBase); virtual;
       function    GetParent: TfpgWindowBase; virtual;
       function    GetCanvas: TfpgCanvasBase; virtual;
  
positive.code:     GetPropList(Obj.ClassInfo, tkPropsWithDefault, PropInfos);
      { Loop through all the selected properties }
      for Loop := 0 to Count - 1 do
        with PropInfos^[Loop]^ do
          { If there is supposed to be a default value... }
          if Default <> NoDefault then
            { ...then jolly well set it }
            SetOrdProp(Obj, PropInfos^[Loop], Default)
    finally
      FreeMem(PropInfos, Count * SizeOf(PPropInfo));
    end;
  
negative.code:   // If you have to convert this to an Integer, mrNone = 0 etc.
    TfpgModalResult = (mrNone, mrOK, mrCancel, mrYes, mrNo, mrAbort, mrRetry,
        mrIgnore, mrAll, mrNoToAll, mrYesToAll);
  
    TfpgDragAction = (daCopy, daMove, daLink);
    TfpgDragActions = set of TfpgDragAction;
  
  const
    MOUSE_LEFT       = 1;
  