What I mean is that a map placed in an item frame shows not only the map's pos but also placer's pos. Confirm by following:
1. Open a SMP server and obtain a map and a frame.
2. Place the frame then the map into.
3. Move this player away and another player come and see.
Then the second player will see a green spot and unexpectedly a white arrow pointing the first player.
Chunk Update?