I have situation of 2 divs, each one other height, both need vertical-scrolling as they are higher then screen 100% height.

My ui-person want them to scroll together, then I put the scroller on the parent div.
But he want each div to scroll only till it finish its own content.
For example, in the following situation – the ‘fat’ board is my screen:

After finish scrolling, He don’t want the result to be like this:

But like this:

Is there any option to do that? I don’t find one.