Popups in Vaadin Grid


I’m sitting with a project, where I’m trying to get small popups with information, and I thought I’d try to use the Vaadin Grid, since it seems very flexible.
I absolutely love the example found at: https://demo.vaadin.com/sampler/#ui/layout/grid-layout, but the sourcecode is a bit vague (Or I’m stupid, one of those :-D), but I just can’t seem to find out how to get the small popups which is shown in the example.

Anybody here that can be of help?

Best regards