Heather,Lilly has been doing this for ages, and is much better now. Just be consistent with whatever you do. I have found that L does it when she is seemingly being ignored (she's not, but I may be doing something in the kitchen, say for bfast), if our dog is around (she likes to share.....), and if she is not hungry enough. We also make sure she stays at the table until we are all finished, and must say she takes longer than us.
She loves to eat stuff from my plate with my fork too. I don't mind at the mo as she is at least eating! I tend to put it on her plate and she has her own little metal fork that looks like mine.
I've been at this for more than 6months!! and it does improve. Just be consistent. What I did was if she did it too much, I told her she must be finished, take all the food away from her and move her away from the table.(while in her chair) and bring her back when she has calmed.
hth