Have you tried taking her aside and telling her about this problem ... in a nice, tactful way? I probably wouldn't chose the holiday itself ... but some other time. She may not realize how much of a problem she's really causing. I am the more forthright one in my family and have had to do this a lot. I feel your pain, though!!!

I really feel for you- I have a friend in a similar situation where one of the sister-in-laws is constantly nagging, lying, and just taking advantage of their in-laws. My only advice is to have a chat with your husband- is this his sister or his brother's wife? Someone definitely needs to speak to her but I think if it came from you instead of a sibling, it may make things more tense for you. The siblings need to stand together and tell her that she is putting their parents in a difficult position when she constantly does this on every occasion. I really understand what you are going through but would hate for you to be singled out if you speak up.
She needs to be told to stop changing plans and stop being so demanding or no one will be com ing if she is there. Good luck!

Thanks for the great advice. My tolerance level for her after all these years is at zero, so my husband the other siblings will handle it. I agree that the information will be "recieved" better (if at all), if it came from one of the family members. It's all for attention, after all of the changes yesterday she walks in only speaks to my mother in law, begin to prepare her dinner as if she gonna sit down to eat, but the next thing we know she walking out with her plate wrap in foil...I wanted to drop kick her....i'm not even gonna lie. So just filling you in on how the b.s ended...lol. My FIL took my mom in law out to brunch after church so her morning was peaceful, but you can see how "the kids' not speaking and refusing to be around each other is getting to her even if she dont say anything.

Goodness, after all that she didn't even stay!

That's unfortunate that that happens! Hopefully someone in the family with speak to her soon and end all the drama.

As much aggravation as this causes, I highly doubt that an end is going to come anytime soon. As long as her parents/family allow her to dictate what,where & when things are going to happen, you are just going to have to get used to accommodating her every need. You cant be the one to stand up to her, that might cause even more drama for you.
Sorry.

You can always plan your own celebrations with the people that need to be celebrated. Take your MIL out to lunch for Mother's Day- even if it's a separate day. Refuse to participate and enjoy yourself with something else. Just because everyone else is doing it does not mean you have to do it. If anyone asks, just tell them that you were looking forward to "whatever was planned" and went ahead and did it by yourselves. Good luck!