Why can't I see horizontal scroll bars in Finder? I have a MacBook, with el Capitan.

I am in Finder, looking at a folder which contains a lot of files. I have arranged by kind, which means that I have to scroll horizontally to see all my folders. But there is no horizontal scroll bar. The only way I can scroll is by using the arrow keys. This happens in any folder in icon view using Arrange By kind, where there is so much content that you need to scroll.

I tried going into Settings | General | and selecting "Always" for "Show scroll bars" but it made no difference.

Does anybody know how I can fix this?

This is what I see:
You're not missing anything, this is just how Apple chose to design this view, presumably because there could be hundreds of items of each file type, but they wanted to show as many file types as possible at once. You have to scroll through using the arrow keys, by two-finger dragging, or using Shift-scrollwheel (I assume&mdash;I don't have a mouse to hand). Or you can click "Show All" to show all the items arranged in a more conventional grid.

The "stacking" of folders at the right hand side is meant to be the visual cue that this is the case.