internal void DeleteTimeBoxes(TRB_PART part, TRB_STATE state)
 {
     TimeBoxCollection.RemoveAll(trb => trb.HasState(part, state));
 }
 internal void ToggleState(TRB_PART part, TRB_PART where, TRB_STATE state)
 {
     TimeBoxCollection.ForEach(trb => trb.ToggleState(part, where, state));
 }
 internal void SetState(TRB_PART part, TRB_STATE state)
 {
     TimeBoxCollection.ForEach(trb => trb.SetState(part, state));
 }
 internal void UnsetState(TRB_PART part, TRB_PART where, TRB_STATE whereState, TRB_STATE state)
 {
     TimeBoxCollection.ForEach(trb => trb.UnsetState(part, where, whereState, state));
 }
 internal void SetDateTime(TRB_PART part, TRB_STATE partState, DateTime dt)
 {
     TimeBoxCollection.ForEach(trb => trb.SetDateTime(part, partState, dt));
 }