CustomEditor and inherited components

I have two classes (base and inherited) and one custom editor component for base class.

Base: 1)

 public class HF_Manager : MonoBehaviour
 {
     public virtual void OnUpdateData() { }
 }

And inherited: 2)

 public class HF_ChairsManager : HF_Manager
 {
     public override void OnUpdateData() { /* special case */ }
 }

And I have a CustomEditor script for base class (HF_Manager):

 [CustomEditor(typeof(HF_Manager))]
 public class HF_ManagerEditor : Editor
 {
     public override void OnInspectorGUI()
     {
         DrawDefaultInspector();
 
         if (GUILayout.Button("Update Data"))
         {
             HF_Manager t = (HF_Manager)target;
             if (t != null)
                 t.OnUpdateData();
         }
     }
 }

My task is to make "Update Data" button for each inherited component, which should fire HF_Manager's OnUpdateData() method.

But now I see "Update Data" button only on HF_Manager component...