My current implementation of AutoAdjust region will actually first "grow" the region and then contract it -- that can make it easier in some rare cases, but I'm thinking it's probably less confusing and more generally useful if it never expands the region and ALWAYS contracts around whatever you have selected...
I have disabled the "grow before shrink" action, as I think it could lead to some confusion. Ideally I will put back a grow mode in a different place, as it could be useful for selection some regions in some scenarios.