In the original X-Com and in TFTD on the battlescape, you could use the selector cuboid to discern the terrain and location of objects in unexplored areas, because the terrain and objects would occlude the selector even if they were unseen. I don't know about others, but I abused this to send blaster bombs around unexplored corners to hit distant targets early on in a mission, such as killing every ethereal leader and commander on the first turn.
OpenXcom preserves this behavior.
In X-Com: Apocalypse, this was disabled, the selector would not be occluded by anything in undiscovered terrain.
I'm asking if there could be an option added to turn off selector box occlusion by unexplored terrain. Normally my solution to such a thing is "don't use the exploit" but I'm so good at doing it that I have to be very careful where I place my selector just to avoid revealing terrain. It could sweep across a segment, being rendered in 3 positions within the blink of an eye and I'd already know exactly which terrain block is in that part of the map, and I can't shut off this ability.