Are nested `<th>`s supported by the tree-table implementation?

https://github.com/mleibman/SlickGrid/blob/7a3f3dcfafe6222c5c9c581589c9fb5c185602b7/examples/example5-collapsing.html#L1-L278

The aforementioned supports nesting <td> and <th> rows in the <tbody>. However, does it support nesting <th> column headers in the <thead>? I ask because sometimes I want to indicate that multiple headings are part of a group.

As a poor demonstration, consider the undermentioned:

xml复制

<th colspan="3" scope="col">
	Attributes
</th>
	<th colspan="1" scope="col">
		<code>Lang</code> Attribute
	</th>
	<th colspan="1" scope="col">
		<code>Class</code> Attribute
	</th>
	<th colspan="1" scope="col">
		<code>Type</code> Attribute
	</th>