Hi,
first of all thanks for great project and contributing it to the community. I started my Java adventure with vaadin and it seems that is things I looked for.
But I faced small nuisance, which, I suppose, could be easily solved.
During development, after redeploying to tomcat, application in my browser remains unchanged. Only browser restart or deleting cookies force my browser to get newer version of application. I tested it on Firefox, Chrome and IExplorer.
Any idea, how to improve that?