War Room launches with your villages listed according to the distance to your target.
When you choose to attack a different village, the war room launches again, with the village list again refreshed according to the distance to the target.
When you do not want the list of villages to change, "PIN" the war room. When PINNED, list of villages does not change, just the distance to target is updated. (Just tap the blue pin icon in the upper right corner to set or reset this option)
PINNING will come in handy when you want to launch multiple attacks from the same village, or set of villages.
Example: Here we have a PINNED list. Notice that when the target changes, the villages listed stay the same (but the attack distances recalculate). Handy!