The Day of Chocolate(2018)

Original title: Dzień czekolady

Through the window, Dawid watches a new neighbour move into a house next door. The girl is more or less his age. She's wearing a strange skirt. Later on, Dawid finds out it's a Hawaiian hula skirt and the girl's name is Monika. Most probably, he also learns why Monika's grandma has gone away to Hawaii.