The show bar's "sharing" check box looks like this:

If you check the "sharing" box then the sharing status of all items is displayed.

For instance, in the following image the manila folder indicates that the document "Possible Print Ads" is shared, and on the right side is displayed whom the item is shared with and whether they have edit rights.

When the sharing box is checked the "all folders" box is also checked automatically so that all folder contents are displayed whilst the sharing information is displayed. It is an easy matter to scroll down looking for the sharing status of items since they are marked with the visible manila folders and user names.