How to remove page extension?

Question

HTML

Hello. There was a problem from the expansion of the page and the appearance of scrolling on it.
In fact, there really are elements on the page that, in principle, stretch the page. The catch is that these elements are in a block with properties

#block {
        overflow-x: scroll;
        overflow-y: hidden;
        white-space: nowrap;
    }

Yes, the block has scrolling, and elements outside this block are not visible. And yes, the block is within the browser window, but there is still scrolling at the bottom. I've drawn here what it actually looks like.

Where, the green frame is a block; yellow frames - elements; yellow dotted - not visible elements; red line - right border of screen/browser_window; the white area is the page.
The diagram shows that the page has parted due to the elements.
Here are real screenshots

PS: In this example, the same thing, but the page does not move around.
UPD: Here's what I'm working with. There is one inconsistency here. The fact is that everything works as it should on jsfiddle. Those. the "block" itself has a scrollbar (#house) in which there are elements (.sector). On the source, #house also has scrolling, but in addition to everything, the page also has scrolling, as if #house does not have its own overflow properties and does not hide elements outside. Unfortunately, I cannot give access to the page where this was done.