ListGrid opened group empty & SummaryRow css class

Hi,

http://www.smartclient.com/smartgwt/showcase/#grid_summaries_featured_category

Choose any row and modify its category.
A new group appears opened but empty.
Closing the group and reopening it change nothing, the group is still empty.

And why do the summary row has a listGrid css class ? Is there any way to change this class ?

Tested on Chrome 31 & FF 26

Thank you