Add "mark all files in this folder" to enable quickly selecting duplicates that share a folder

[jrkoop]

Today, it seems I can only select one file at a time. When I have hundreds or more duplicates, this becomes so time-consuming that I wind up aborting. Rather than having to select one or more files in each group of duplicates, it would be faster if you could right-click and select "mark all the duplicates in this folder." This way, you can quickly iterate through what can sometimes be long lists. Many times, multiple duplicates share the same folder. Therefore, this enhancement would very likely be used often.