TCustomControl不会触发Paint方法

Question

我有以下代码：

tExCustomControl = class (tCustomControl)
private
  procedure Paint; override;
end; 

tMyControl : class (tExCustomControl)
private
  procedure Paint; override;
public
  constructor Create (AOwner: TComponent);
...
end;
...
implementation
{ tExCustomControl }
procedure tExCustomControl.Paint;
begin
  inherited;
  ...
end;

{ tMyControl }
procedure tMyControl.Paint (Sender: TObject);
begin
  inherited;
  ...
end;

它工作正常，但出于某种原因，现在并没有触发任何一种Paint方法。谁能告诉我什么是错的？感谢。