Reference TControlHintWindow

  TControlHintWindow = class(THintWindow)
  public
    { Create a new hint window }
    constructor Create(AOwner: TComponent); override;
    procedure ActivateHint(Rect: TRect; const AHint: string); override;
    { Show or hide the hint }
    property Active: Boolean read FActive write SetActive;
    { The control the hint is shown over }
    property Control: TControl read FControl write SetControl;
    { The point in the control where the hint is shown }
    property Point: TPointI read FPoint write SetPoint;
  end;