Selection Zones allow you to make a selection and then refine your selection even further from what you've already selected.
Protection Zones exclude areas that you do not want to be used in a selection. A Protection Zone is the area outside a Selection Zone and vice versa.
Here are some examples of how you could use them:
Problem: I'm using the magic wand and I want to make a selection of the sky which ranges from a very light blue to a much darker blue. However, there is color fringing in the trees that make the branches a darker blue, too. I begin by selecing the light blue in the sky, which includes all those litte "holes" between the leaves, branches, and those tricky dark blue branches. But, when I go to select the darker blue portion of the sky, the dark blue branches are also selected ruining the previous work. This cannot be done with 2 separate selections then merging them because you end up with the same problem.
New Feature "Protection Zone": PROTECT the original selection by drawing a "Protection Zone" around the originally selected area so that the dark blue branches are also protected against being selected. The "Protection Zone" could also be a previous selection (but not in this case).
This feature can be used after you make an initial selection to protect it. Or, you can make a "Protected Selection" right off the bat to exclude a certain area from future selections.
With this feature, you would solve our original problem by first making the selection of the light sky. Draw a rough Protection Zone around the area of the selection that includes the dark blue branches. Then, make 2nd selection using magic wand of the darker sky to add it.
A very simply example would be if you had a handful of blue flowers in the prairie that you wanted to select, but there is a blue sky above of a similar tone. You would first draw a rough protection zone around the sky to exclude it from the selection and then move ahead with a selection the flowers with the magic wand.
New Feature "Selection Zone": When you create a selection zone, anything within the zone is fair game. Anything outside of the zone is excluded or protected (the Protecion Zone).
So, in the last example, we had only one type of blue flower. But, what if there were two species of blue flowers and you only wanted to select the blue in one of them? You could simply draw rough selections around the flowers of the species that you want to change (using Shift-Click to add several selections). Then, convert this rough selection into a Selection Zone. Then, you can use the Magic Wand tool to select only those tones within the Selection Zone.
Now, let's say that you had a situation where you got really really close to the selection you wanted, but the selection you ended up with in the Selection Zone with the Magic Wand tool needs further refining. For instance, within the Selection Zone there are some unwanted blues in some wet leaves that reflect the blue sky that were selected. So, you would now redraw a new winding and turning Selection Zone around the current Magic Wand selection that would exclude those blue leaves. And, you'd end up with only the blues selected in the flowers that remain from the Magic Wand selection. In this case, you have a very fast way of deselecting certain things.
Essentially, you can make a selection, convert that selection into a Selection Zone, and then refine the selection even more within the Selection Zone. You can repeat as often as you wish.
This makes for a very nice way for refining selections in a kind of hierarchical manner as if you wanted to refine the results of a search. You'd do a database search and, from those results, do another search.
I've been wanting this feature for many years.