Grid show nothing

I am using a Grid to display a List of data bean.
Everything is working fine in Vaadin 7.5.x.

When I upgraded to the latest Vaadin 7.6.1,
Grid shows only the title row, but all the data rows are not displayed.
I checked the HTML DOM content, there are a tr in the thead, but nothing in the tbody.
Looks like no data row is created into the HTML DOM.

If I downgrade to Vaadin 7.5.x, everthing working fine again again.

Is this a bug?

Hello, please ensure your widgetset is up to date. You can check this by using the ?debug query parameter and checking the second tab of the debug window - the server and client version numbers should match.

I used the ?debug query parameter to check it, and found out “Client engine version” is 7.5.10.
Looks like my widgetset is too old.

So I rebuild widgetset in Eclipse, and re-deployed the app.
Now everything is working fine.

Thanks very much for your help!