Defines UxmlTraits for the ToolbarButton.
| ToolbarButton.UxmlTraits | Constructor. |
| uxmlChildElementsDescription | Enumerator to get the child elements of the UxmlTraits of TextElement. |
| canHaveAnyAttribute | Must return true if the UXML element attributes are not restricted to the values enumerated by uxmlAttributesDescription. |
| uxmlAttributesDescription | Describes the UXML attributes expected by the element. The attributes enumerated here will appear in the UXML schema. |
| uxmlChildElementsDescription | Describes the types of element that can appear as children of this element in a UXML file. |
| focusable | The focusable attribute. |
| focusIndex | The focus index attribute. |
| uxmlChildElementsDescription | Returns an enumerable containing UxmlChildElementDescription(typeof(VisualElement)), since VisualElements can contain other VisualElements. |
| Init | Initialize EnumField properties using values from the attribute bag. |
| Init | Initializer for the UxmlTraits for the TextElement. |
| Init | Initialize a VisualElement instance with values from the UXML element attributes. |
| Init | Initialize VisualElement properties using values from the attribute bag. |