I lose a significant amount of time trying to line up rooms between floors (it tends to be the case that going between floors on a single map graphic, that we want it to not "shift" when going up/down). If there were a toggle to snap rooms to another room's dot, it would be a very nice time and annoyance saver.
This snap-to would need to operate in both "Create" and "Move" functions, if at all possible. ,'
Most of the time it feels better if the "room" circle doesn't jump when going up/down. (occasionally i've used the jump to signify the way the stairs curl around, putting you in a slightly different placement. So, if it is easy enough to do, could be nice.