I tried to use the new mapping feature in the snapshot, whereby when you right click a map into an item frame, the map would take up the space of the entire block.

However, upon right clicking with a map to see this feature, the item frame stayed the same, and whats more there was a ghost of the item frame that followed the cursor. And whats more...there was four of them. This persisted even after restarting the game, and even after removing the item and the map from my inventory.