A control that is both a toggle and a dropdown used with EditorToolbarElementAttribute.
| dropdownClickable | Clickable object for this dropdown. |
| icon | 与元素关联的文本。 |
| text | The icon associated with the element. |
| EditorToolbarDropdownToggle | 构造函数。 |
| SetValueWithoutNotify | 允许设置值而不接收更改通知（如果有）。 |
| dropdownClicked | Action triggered when the dropdown is clicked. |