void ReferenceTimeGUI()
        {
            if (!state.IsEditingASubTimeline())
            {
                return;
            }

            EditorGUI.BeginChangeCheck();
            state.timeReferenceMode = (TimeReferenceMode)EditorGUILayout.CycleButton((int)state.timeReferenceMode, k_TimeReferenceGUIContents, DirectorStyles.Instance.timeReferenceButton);
            if (EditorGUI.EndChangeCheck())
            {
                OnTimeReferenceModeChanged();
            }
        }
 public static int CycleButton(int selected, GUIContent[] options)
 {
     Styles.Init();
     return(EditorGUILayout.CycleButton(selected, options, Styles.preButton));
 }