I have been mulling this over and decided to post because I cannot decide if/how to react to this and it is on my mind.
DD's friend has been picking on her. I think it started because her so-called friend fell out with a couple of other girls and wanted DD to take her side - but DD didn't want to join in. She ('friend') is perhaps punishing DD for this ('friend' has apparently made up with the other girls but not DD). She started picking on DD (following her around, trying to wind her up), but is now just ignoring her.
There's a bit of a history of this sort of thing going on - DD really likes this girl, and she can be nice/fun but has become a lot more 'pushy', likes to hang out with some of the 'louder' girls. Unfortunately DD really wants to be her friend and I think she is using this to get at her/hurt her.
I am not sure whether to leave it as it's nearly the end of term, but I have offered to take this girl to an activity during the summer and am now really reluctant to do so. Also their teacher is probably fed up with having to deal with all the squabbles that go on (and there have been plenty over the last year, including DD and 'friend' falling out on a fairly regular basis).