private void OnGUI() { EditorGUILayout.HelpBox("This spinner icon is drawn using the Spinner utility class.\nThe animation is updated using the Update() message of EditorWindow. But when it comes to a custom inspector script (by inheriting from Editor), you must override RequireConstantRepaint() to make the GUI be repainted each editor frame.", MessageType.Info); EditorGUILayout.Space(); Rect rect = EditorGUILayout.GetControlRect(false, SPINNER_SIZE, GUILayout.Width(SPINNER_SIZE)); rect.x += SPINNER_OFFSET; m_Spinner.DrawGUI(rect); }