The Edit > Locate Filter command opens the Locate Filter dialog box, which allows you to indicate the type of items you want to select in an area you indicate. When you use the Select Tool and drag a fence around an area, only the items you indicated in this dialog box will be selected (for example, markups. When you select All, the entire area you indicate is selected.
Once an area or one or more items are selected, you can copy, modify, or delete them.
A Locate filter field is also available on the Markup Ribbon toolbar.