I'm very new to GXT and webapp.

I have created a class that extends GridView<M>, I can configure the number of columns, the columns header and display some rows, it works.

I would like to add a header for each rows, this header should have the same look and feel as the column header.

I cannot find any information about this, Is there're a way to add a row header? Is there a tutorial or some examples?
Thanks for your help