Is anyone here using there built in bed divider? What are you using? I had some 1X4 pieces of wood and cut one to size. It works good keeps all my grocery from scattering all over my bed, but it's a little to thin moves around a little bit in the grove it sits in. So I'm thinking 2X4 will work but it looks like it will be a really snug fit, which is okay when dry but might get stuck if it gets wet and expands. So Before I go buy a full length 2X4 is anyone using it already with opinions on it.