Changes

I lately notice that Aliya attitude changes with each person. If she is only with me she listens and makes more or less everything I ask, or she tries to get something and based on my reaction she knows if she can continue to throw herself on the floor or not. Then comes her father and there she goes a completely different set of behavior to get what she wants. On my birthday we went to a place to eat and there was a younger boy on the other table. I just couldn't recognize Aliya! 6 months ago she will give her toys to the other kid. Now she had a tantrum just because I gave him her balloon which she wasn't playing with. I really felt that something in between the kindergartens has changed in her and I need to put more effort to play and know her. Maybe I am too soft? Although I don't believe in beating, maybe this is more correct to do?