well first when ur trying to make ur child understand that something is wrong no one should interfere .. cause then they no its a way out . u need to tell ur mil in a nice way that some manners have to be taught and it becomes difficult to handle the baby when ur socially meeting people.. children are old enough now to understand right and wrong.  u should encourage your mil also to help in teaching your baby whats acceptable and what isnt.

I think don't be harsh on the MIL in front of Baby...ask her to take a back seat n handle the situation

Kids are very smart now a days. A healthy chat with your MIL will help settle things. Even my kid has this habit in her 2 year. They will learn from others or TV or sometimes it's just natural. Now that your baby is grown up.. take baby out and tell gently that...these behaviours are not proper, not good. It's not how a princess will behave. For me... books helped me a lot as asha said. And also.... I showed some kids who behave like this and said... how bad it looks. We have to keep saying and stick to our reasons. My sister in law always use to say so..and that made things worse. So...I spoke to my husband and asked him to talk to their family. Thank God.. things settled. Very rarely she tries to show some attitude. whenever she throw any toys... immediately I will pick up and pack it..saying..you are not caring...I will give to that person who will care and love toys. Now she is fine.

hi anon pepper books help a lot for good manners etc. everyone has given u awesome advice. tc & good luck!

this is happened at our house a lot.. the only way out is to sit with your mil and explain her why is it important to be assertive at times...