Not sure if this is the same request, but I would dearly like the ability to expand/reduce selections...as well? In my case, the purpose is so that I can adjust the edges of a selection more finely after the selection box is created. Sometimes, in order to get the area/object I want, I can't actually start the selection box near the object on the screen so I have to make my best guess about where to start. That guess might be off by a few pixels, might be off by a lot more. If the selection box had handles and could be enlarged/reduced, then I could fine-tune the 'fit' and not be stuck trying again and again, or trying to make a series of boxes work/match when one would do it.
I know the lasso lets you cut it close but trying to control a mouse to cut it close is a real pain, and sometimes you want a straight edge. For example, think about trying to select an odd-shaped object. I want it in a square shape with a 1 pixel cushion at its outermost parts. As things are now, I don't know any way other than trying over and over to find the exact right starting point to give me the perfect sized selection box, or selecting and then trimming the individual sides, or I can cut away everything around it with a series of selection boxes that have to be lined up perfectly.
OR, ideally, you could put one imperfect selection box around it, enlarge or reduce the various sides as needed, and be done.
Hoping that makes sense because if there is a way to do this that already exists, I would dearly love to know it.