Extending Button's editor window.

I’ve extended “Button” with my own script, but any public properties or fields I add to my button doesn’t appear in unity.

What i think is going on, is a custom editor window has been defined for Button, and “myGameButton .cs” which extends ‘Button’ also gets the custom editor window, which isn’t designed to show the new public fields of my new extended button script.

/// <summary>
/// This class extends Button, allowing custom code for all on screen buttons
/// </summary>
public class myGameButton : UnityEngine.UI.Button, IPointerClickHandler
{
        public UnityEngine.UI.Text HelpText;
        ...
}

in the above instance, i want the reference for “HelpText” to come from unity’s ‘drag and drop’ functionality.

Are my assumptions as to why it’s not working correct? and can I extended the custom editor window to accept my new requirements?

Found it. UI.ButtonEditor

public override void OnInspectorGUI()
{
            base.OnInspectorGUI();
            myGameButton button = (myGameButton)target;
            button.HelpText = (UnityEngine.UI.Text)EditorGUILayout.ObjectField(new GUIContent("Help Text"), button.HelpText, typeof(UnityEngine.UI.Text), allowSceneObjects: true);
}