In this pic from @brent you can see the 'triangles' I'm referring to (circled in white), they are in the 'right pane' (outlined in the right red box, 'left pane' is outlined in the left red box).

However, in this pic from my laptop you can see all the folders in the 'right pane' do not have the 'triangles' to open the folders in the right pane. You can only open them by clicking on them but then it opens only that folder, so the 'tree' structure does not work in the 'right pane'.
