At first I was a little worried because some of the reviews state that the sides/arms come off easily. I was even more disappointed when I received it and mine was doing the EXACT same thing, arms coming completely off when the baby was trying to use it. BUT!!! I had it on wrong, as I suspect most parents did at first, and once I pressed down SUPER HARD and it clicked in (okay, I actually had my husband do this part), there was no slipping out again!! I hope this helps with anyone having this issue. It really did seem like it was clicked in and together the first time, but it goes down even further and really is sturdy after that.
Anyway, no complaints! My 34 lb two year old loves it and it's easily taken indoors and outdoors.