By default, the results list shows all items that are the results of the current search or navigation view, or the contents of the current folder. Often, this is sufficient to find the items that you are looking for. However, you can further refine the results list by adding a filter on any visible column.
To add a filter:
for the column upon which you want to filter the results list. The column menu appears.
appears to the left of the column heading.To remove a filter:
for the column for which you want to remove the filter. The column menu appears.