FixedHeader fixed left column in wrong position when <th> elements are different heights

When FixedHeader is used with {'left':true} and the <th> elements are different heights, the positioning of the left-most column can be wrong. See http://live.datatables.net/onuhuh for an example. Apart from enabling FixedHeader for the example, all I did was change "<th>Engine version</th>" to "<th>Engine<br>version</th>".

Any suggestions?