wicket - inner class in wicket

Question

I have 3 class A,B and C that B is in class A and C is in class B so C -> B -> A and I named My html as A$B$C.html but I got this error :

Can not determine Markup. Component is not yet connected to a parent
Markup not found execption: ...

EDIT - for example like below:

public class A extends WebPage {
  public A(){
   ...
  }
  private class B extends AbstractColumn<T,String> {
    public B(){
     ...
     }
    private class C extends Panel{
      public C(){
        ... 
       }
    } 
  }

}