To define a new selection area when other areas are selected, the previous areas are cleared by default. Follow this procedure to add the new selection to selected areas you have already defined.
Any combination of selection tool boundaries can coexist as a cohesive selection. Scan Regions and Clipping function as normal, regardless of your quantity and variety of selections.
You can only use this method for the most recently created selection set or Scan Region. To remove a selected area from a selection set you are creating, use the following simple method:
Use this method to remove all selection sets you have created.