[DRG]

If anyone wants to test that this works the simplest way is to build a plain map using one of the large rectangular factory buildings then hammer the upper left hex it sits in with heavy arty.

Only the structures that had a physical part of the building in that upper left hex it occupied did the disappearance trick. It will probably vary depending on computer speed and what else you might be doing but I have found sometimes you cannot see it happen ( wink out then back in again ....) even when looking closely but sometimes it does a slow 1/2 second blink

But, it will come back now which is the important part