public FoldoutColorField() { m_ColorField = new ColorField(); m_ColorField.name = "field"; m_ColorField.AddToClassList(k_FieldClassName); m_ColorField.RegisterValueChangedCallback((e) => m_MixedValueLine.style.display = DisplayStyle.None); header.hierarchy.Add(m_ColorField); m_MixedValueLine = new VisualElement(); m_MixedValueLine.name = "mixed-value-line"; m_MixedValueLine.AddToClassList(k_MixedValueLineClassName); m_ColorField.Q <IMGUIContainer>().hierarchy.Add(m_MixedValueLine); }