DS, almost 3, has developed the habit within the last week of having to do two things at once all of the time. If he's reading a book then he will have to be picking up small toys whilst he's reading, sometimes he will be flicking through two books at once. It's as if just doing one thing at a time isn't interesting enough for him any more. Not sure whether this is something that will quickly pass or whether I should be trying to nip it in the bud. I find him quite difficult when trying to do an activity with him as he always has his eye on doing something else at the same time. Not sure what to do?