embedding vaadin in existing web page, expand to use available space

I am looking at intergrating Vaadin into an existing webapp. For this purpose I need to be able to embed the Vaadin app in our standard page which has existing menus, logs & footer.

I need the Vaadin app to expand to fill the available size within the container (Div) in which I am placing it.

I’ve used the example from https://vaadin.com/book/vaadin7/-/page/advanced.embedding.html, item 11.2.1.

When I set the size of the containing div to 100%, the Vaadin app size collapses to 0.

Am I doing something wrong, is it possible, can someone provide some sample html, css & Vaadin code?

Thanks

As it turns out it was actually the html on the page that I was trying to add the vaadin component to that was causing the problem.