Stop Finder window sliding to left. Show scrollbars

Can someone help please.

I have Finder in List View. I have the sidebar on the left.

There don't seem to be any scroll bars visible, although they do flash up from time to time.

When I click on a directory on the left, eg documents, the list opens on the right.

Sometimes, (and I can't reproduce it to order) the list of documents slides to the left under the sidebar, so I can no longer see the directory name I am working in.

Sometimes, if I fiddle around, a scrollbar appears on the bottom and I can slide the list to the right again and see the left again. (But I can't reproduce it to order, either.)

How do I stop the finder window sliding to the left?

How do I ensure the scrollbars always stay visible?

There don't seem to be options for this under preferences or View Options.