Third column added to folder view

I don't know if this is something new or if I just never had it happen to me before. When I open a folder with songs listed, a third column is being created on the right side. It has the artist, title at the top, an icon to represent the song, then the same list of properties in a column that is in the row at the top of the folder window. You know, things like bit rate, length, when created, etc.

This new unwanted window within the folder window keeps me from being able to expand the columns of data that I've selected when listing songs in the window.

I've found that I can make that third window go away by grabbing the right margin of the window and dragging it towards the left. At some point the window remaining will get too small and the third window will go away. But when I drag that margin/border back far enough to the right, it pops up again.

I wish I could make it go away permanently, but I don't know what causes it to appear. This just started this month. Any answers appreciated.

Thanks so much. I never knew I clicked on that switch. Sure didn't know what it did.

After several years with Windows 10 by now, I don't know what most of those things in the ribbon do. Saw no reason to investigate them as long as it was doing what I wanted it to.