UV Editor: Scale selected UV islands to unselected UV islands.

Currently Average Island Scale requires multiple islands to be selected, and will average their size relative to each other. This is useful if none of the islands are packed yet. If the islands you need to reference are already packed, average island scale will mess that up a bit with the new size.

Scaling a UV island (or islands) to other unselected islands (without affecting the unselected) would also be useful. A 'scale to other islands' operator.

ps. there is no tag for the UV Editor