有谁熟悉TFlowChart的？如何给里面的图形加上hint?

谁用过TFlowChart？
里面一个类是这样定义的：
TdxFcItem = class(TPersistent)
private
  FOwner: TdxCustomFlowChart;
  FText: String;
  FFont: TFont;
  FRealFont: TFont;
  FParentFont: Boolean;
  FDestroying: Boolean;
  FSelected: Boolean;
  FRepainted: Boolean;
  procedure OnFontChange(Sender: TObject);
  procedure SetRealFont;
  procedure SetFont(Value: TFont);
  procedure SetParentFont(Value: Boolean);
  procedure SetSelected(Value: Boolean);
protected
  function SelList: TList; virtual; abstract;
  procedure Changed;
  procedure FontChanged; virtual;
  procedure Invalidate; virtual; abstract;
  procedure LoadFont(Stream: TStream);
  procedure SaveFont(Stream: TStream);
  procedure SetText(Value: String); virtual; abstract;
  procedure ScaleFont;
  property RealFont: TFont read FRealFont;
public
  constructor Create(AOwner: TdxCustomFlowChart);
  destructor Destroy; override;
  procedure Assign(Source: TPersistent); override;
  property Destroying: Boolean read FDestroying;
  property Font: TFont read FFont write SetFont;
  property Owner: TdxCustomFlowChart read FOwner;
  property ParentFont: Boolean read FParentFont write SetParentFont;
  property Selected: Boolean read FSelected write SetSelected;
  property Text: String read FText write SetText;
end;然后TdxFcObject从这个类继承，添加上paint方法。
我想让这个类能实现hint的功能，也就是和Label, button这些都有的那种hint, showhint属性
我改怎样做呢？我试过CM_MouseEnter和CM_MOUSELEAVE，但是没有反应，我也不好把
TPersistent类改成TCustomControl，那样procedure Assign(Source: TPersistent); override;我就不知道怎么改了