Tab key troubles

Hi, I’m using Vaadin with Liferay in a portlet and I have a problem with the Tab key in a modal window.
When I set the TabIndex for each component (in a form) and then try to browse through it (with the Tab key) it works just fine, until it comes to the last TabIndex and then it jumps outside the window to the header of the Liferay portal. Any thoughts on how to stay in the window? Thanks.

I think we can’t force the focus to stay inside a single portlet. The modal focus management works only inside the app, not for the whole visible page.