Variable height groups getting bigger endlessly when scrolling down

Hi everyone,

I’m building a page in responsive design, it contains a larger group having the size set as 100% width and 100%, plus some sub groups, inside this larger group, having its height set as variable, as a % of the page total height. (so the sub-groups height can vary in the same proportion as the background image size, so elements inside this subgroups will be always positioned at the same spot in relation to the background image)

For me, it all looks good when I preview the design. However, for my boss, when he scrolls down, the sub-groups height gets larger and larger, endlessly, so he can never visualize the end of the page!

Does anyone know how to fix it?

Thank you!