The DOCUMENT STATISTICS Information Window is located under the INFORMATION button on the Accessibility Toolbar.
The Document Statistics lists the different markup tags that are on the page and the statistics for each of these tags. The visibility of the columns can be turned on and off by selecting the Column Selection Icon at the very right of the Column Headers. A checkmark next to an item means that column is visible. To hide a column, select the column name. When no checkmark is next to the item, the column will be hidden.
Try this feature: Open the Document Statistics Information Window for this page. Note the list of page elements. Practice turning the visibility of columns on and off and sorting columns.