Preview pane when opening files on mac

So one of my clients had something very strange happen yesterday.

They are using acrobat pro, and usually they could go to the menu bar along top then file > open and when they did so they would see a small preview of each file they had highlighted on the right side of the "open" window. All I did was switch which folder I was browsing in the "open" window and the preview pane dissapeared and I cannot seem to get it back. I already checked every adobe preference and verified the finder view is set to list with the preview pane enabled. I can confirm if I just open a regular finder window and browse a folder like I normall would the preview pane does show with a small preview of the document I have highligted, however, I cannot get it to show back up in the adobe "open" window. 

For now I have the client using the space bar to show a quick look at the document but this is a lot less convenient than it automatically showing in a preview pane when highlighted. Has anyone experienced this issue and if so how do I get the preview pane to show back up in the acrobat file > open window