Thanks a lot. I tried to post something VERY similar yesterday but my internetconnection seems to be a little ill.
My DM and I still wonder how the mechanics should work: as proposed he took the mini for an invisible enemy from the battlegrid, but what if you fight in darkness or if one PC and one NPC are invisble?
It is not possible to hide the positions and have effects like: If they are standing in the same square they become visible;
Do you have any problems or thoughts about it?
Is there already a thread about it? (Cause I really don't find a search button anywhere)
You can still tell what square an enemy is in, even when invisible, unless they're using stealth. It's rare for my monsters to do that, but when they do I take the token off the battlemat. If the monster is just invisible (not hidden using stealth), I leave the token in place.