There are few cosmetic issues with moving members. First, fields are not movable when caret is on the modifiers or type. It only initiated on field identifier or initalization expression.
Second, when there are regions, they are not taken into consideration and thus some oddity reveals. You can't move member inside empty region, so if you move last member from region, you can't move it back. Also ordering is quite weird when regions are involved. I would suggest including begin and end region tags in the list of targets for swap. This would make it much cleaner in this case.