When the children are playing at your house, I would set the tone. When she snatches a toy, I would take it back and say “We don’t snatch toys here.” If she drops out of a game early, I would say “We have to finish the game.” The little girl will either not want to come back or she’ll start playing by your rules (I hope).

When this really becomes an issue when she comes over at yours to play at your daughter than I would suggest the girls to do non-competative activities together

I think you have done everything you can, and now you have to involve her mother. Try saying something like “yesterday when the kids were playing, I noticed…” and see what her reaction is.

Not sure it’s really a problem you need to deal with as you’re not her mum

We are dealing with similar behaviour from one of our kids. It’s a long game – you really have to work at it for quite a while before you see improvement. I think just being open with her mum and telling her it’s hard to watch them play when her daughter doesn’t engage positively.

Just ignore it. Play the games with the kids and keep having fun after the other one has sulked off. She’ll soon get the message. Not your kid so really not your problem to fix