We bought the tripp trapp chair made by Stokke but after we used it for as few days found that our son (then 7 months) managed to topple it over by pushing himself off against the table and fall back. Problem!!!!!

However we found a seller on Ebay who sells a tray made for the chair. Absolutely a must if you have the chair. It clics on and off so  and secures with a strap through the seatplate and tray. We use it for both our childeren. Seller was very friendly and helpful