public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
    {
        UnityHelpBox target = fieldInfo.GetValue(property.serializedObject.targetObject) as UnityHelpBox;

        EditorGUI.BeginProperty(position, label, property);
        EditorGUI.HelpBox(position, target.text, (MessageType)target.type);
        EditorGUI.EndProperty();
    }
    public override float GetPropertyHeight(SerializedProperty property, GUIContent label)
    {
        UnityHelpBox target  = fieldInfo.GetValue(property.serializedObject.targetObject) as UnityHelpBox;
        GUIContent   content = new GUIContent(target.text);
        GUIStyle     style   = GUI.skin.GetStyle("helpbox");
        float        height  = style.CalcHeight(content, EditorGUIUtility.currentViewWidth) + ExtraSpace;

        return(height > MinHeight ? height : MinHeight);
    }