Override custom inspector for Unity built in components

Question

I'm able to use a CustomInspector for scripts that I have written. Unfortunately this didn't work for Unity's built in Components (such as Rigidbody, Transform...).

I want to hide everything else and only expose 'mass' but this isn't reflected in the Inspector. Instead, if I go to the 3 dots and click properties, it shows the CustomInspector that I've written.

using UnityEngine;
using UnityEditor;

[CustomEditor(typeof(Rigidbody))]
public class RigidbodyEditor : Editor
{
    Rigidbody rigidbody;
    float mass;
    public override void OnInspectorGUI()
    {
        // base.OnInspectorGUI();
        rigidbody = (Rigidbody)target;

        mass = EditorGUILayout.FloatField("mass", mass);
        if (mass < 0)
        {
            mass = 0;
        }
        rigidbody.mass = mass;
    }
}

Answer 1

OK just figured out the problem - I named my class RigidbodyEditor which is exactly how Unity names it in their source code. I changed the name to something else and it works perfectly fine.

using UnityEngine;
using UnityEditor;

[CustomEditor(typeof(Rigidbody))]
public class RigidbodyEditorOverride : Editor
{
    Rigidbody rigidbody;
    float mass;
    public override void OnInspectorGUI()
    {
        // base.OnInspectorGUI();
        rigidbody = (Rigidbody)target;

        mass = EditorGUILayout.FloatField("mass", mass);
        if (mass < 0)
        {
            mass = 0;
        }
        rigidbody.mass = mass;

        GUILayout.Button("hello");
    }
}