Solution 1: click on the black arrow at the right of the hard disk size to show subfolders
Solution 2: In the grid, scroll down until you find the photos you are looking for (you should only have to do this once). Then right-click on one of these photos and select "Go To Folder in Library", which should highlight the folder containing this photo in your Lightroom Folder Panel. You may have to scroll up or down in the Folder Panel to see the highlighted folder.