Another MIL bought my gift question

A few weeks ago I went to a store to return something and ended up buying my kids some things for Christmas. I specifically spoke to my MIL later on to tell her what I bought since I know she often shops at the same store. I told her what I bought and that it was not necessary for her to buy the same things since I don't need 2 of them. This past weekend she told me she went out and bought the same things I bought. She said she was going to give it to my kids and then my kids can leave these toys at her house. It was a chaotic function so I didn't process what she said till yesterday and now Im annoyed. We see them on Christmas Eve and I was going to give the same gift on Christmas day from Santa. I told my husband and he was annoyed but I know he may not say anything since he doesn't want to make a big deal. Do I say anything or just drop it? I usually say what I feel and I hate it because then my DH thinks Im starting a fight. I can give the gift to DS for his birthday a few days before but then what about DDs gift. It just bothers me that she went out after I told her that I bought these gifts and still got them.
Also we don't go there very often and my DS takes his toys that he loves everywhere so for her to say that they are going to stay at her house makes no sense.
Thanks

Re: Another MIL bought my gift question

I would tell her that these are a special gift for Santa so you'd prefer your dc not also receive them from anyone else, and offer to return the ones she bought so the return isn't putting her out.