Good morning!
mspiggy: Somewhat ER is also exhibiting the similar behaviour. If he wants item A, it can't be item B; also on the details on how things should be done (ie process); otherwise he'll throw tantrums. He'll say, "No, not like this/that" and if I revert to his way, he'll say "Yes, like this." It sure looks set to stay.
Re: Jealousy --> beating sis
This seems to be quite common. My fren's son also beat the sis due to jealousy. Do try out sunflower's suggestion. I'm sure it's a passing phase and things will get better over time. It's just a matter of how long this phase will last. So in the meantime, take a deep breath & jia you!!!
sunflower: Oh, small bottles ah... will drop by toyrus again. The last few times I went, the crayola section was v small, maybe OOS.