Right side panel is not displayed 100% height

Hello all.
We are developing a page with scroll. That is, the page is longer than you can see in your screen. We want to show a right side panel to be displayed by click event button. The issue is the panel is not displayed in the 100% height of the page. If the user is in the bottom of the page and the panel is ordered to be displayed, this one is opened at the top of the page. The user has to scrooll up to see the panel. We tried using addon SlideTab and with basi layouts (VerticalLayout), changing height/size properties, but the behavior of the component is the same. We do not know what is wrong. We have Vaadin 13.
Thanks.