public override void OnInspectorGUI() { DrawDefaultInspector(); serializedObject.Update(); firewall = target as Firewall; EditorGUI.BeginChangeCheck(); offsetProp = EditorGUILayout.Slider("Offset from Top", offsetProp, 0f, 3.6f); if (EditorGUI.EndChangeCheck()) { Undo.RecordObject(firewall, "Change Offset"); BoxCollider2D bc = firewall.GetComponent <BoxCollider2D>(); bc.size = new Vector2(7.2f, 3.6f - offsetProp); bc.offset = new Vector2(0.0f, 3.6f - offsetProp / 2); serializedObject.ApplyModifiedProperties(); EditorUtility.SetDirty(firewall); } }