Vertical Scrollbar disappears

I am doing something similar to this sample:

where I add columns and data on the fly. The grid vertical scrollbars only appear when I scroll down the grid. How do I always show the vertical scroll bar at the very first view without scrolling down the grid?

Many thanks.

Nesesito insert HTML code of a page in an application vaadin.
I have a web page with HTML and Java Escript with visual components that can not be found in vaadin and join it even Layaut need an application of Vaadin and to exchange information with the application.