I've been using a car seat in mine but she will not settle in it at all, she will perch, stand inside, stand outside (even though she's anchored to it) and do every other combination aside from sit or lie down nicely. I've been through 3 different seats and they've all had the same effect. When she was smaller I got one which was like a box which was raised and that was probably the most successful one but she grew too big for it quickly.
