Flower girl's mom trouble...

So never thought I would ever have to worry about having trouble with this g's! But I am a little frustrated b/c she asked my FH while I was out of the room but in the same place if she could buy my flower girl another dress for the reception. She didn't give a reason why but what was frustrating is that she did it on purpose while I was out of the room and tried to just get Adam to give her the answer she wanted...
I'm even buying her flower girl dress for her and she is so excited to wear it and we have taken her mom shopping with us to find the dress and she was there for her trying the dresses on and everything. I even came back out to the room they were in and never heard anything about it and my FH told me this morning what she had said and he said at first he told her that it was fine but then said that she should ask me. But seriously I just don't understand why she would wear another dress. There are still going to be pictures taken at the reception and I wanted to be sure she would still stand out and everyone would know she was the flowergirl. Also we aren't inviting our whole guest list to the ceremony so a lot of them wouldn't even know who was what.
I guess the whole thing is just that she asked while I was out of the room and then never even brought it up to me. She will only be wearing the dress for a 15 min ceremony and then pictures so I would really like her to wear it for the reception too...
Anyone else having a problem like this? Am I overreacting? I haven't said anything to her yet!

I don't think your overreacting at all. It totally sounds like she was hoping to pressure your FH into giving her what she wanting. I think she's being completely rude and out of line. She expects you to buy her kid TWO dresses? That's just selfish.

Maybe to not cause any problems tell her "if you want her to have another dress for the reception, you'll have to buy it yourself" and tell her there's no way, with paying for the wedding and everything else, that you can afford to buy her TWO dresses. And if she wants it so bad, she'll have to fork out the money herself. And make sure to tell her it has to be the same color or fit the color scheme too, or good lord knows WHAT she'll pick. That just seems SO rude to me. Would you be willing to let her daughter wear another dress to avoid conflict if she paid for it herself??

If it was me I'd just tell her no way and move on, but that's me. Make sure to tell her how hurt you are that she couldn't even ask YOU the question though.

Why does she feel that her kid needs two dresses anyway? That seems so pointless.

Yeah I wasn't sure how to take it. And it's my brother's fiance...and my niece is sooo excited to wear her dress! She tried one on and was like I'm so beautiful and didn't want to take it off. So I think I'm just going to talk to her about it tomorrow and confront her about it. It made me so mad that she went to him with this type of question! I felt like she knew my answer and just wanted to see if she could get the answer she wanted out of my FH. So we will see. I'm prolly just going to tell her no and that I want her to wear her flower girl dress the whole time!

Well, let us know how it goes! And with it being your brother's FH, that doesn't excuse her actions, it just makes them WORSE. She's supposed to be your FSIL and she's pulling crap behind her back? I wouldn't appreciate that at all. You've done a MUCH better job than I would have in being polite, lol.