The issue isn't so much that he stands in it (which is bad enough) as it is that he likes to sway back and forth and dance while standing, as well as some other not so safe things. A couple weeks ago he added a new spin to this standing in his highchair. He now thinks it's funny to sit on his tray... his tray of FOOD that is. Nice. This is especially interesting when we have pasta... but in all honesty smashed banana (to name just one other thing among many) is just as unenjoyable to clean off the butt of his pants.
In case you are wondering, he took his shirt off (refer back to the "A new 'sport'" blog post a month ago). Aside from his obvious joy in doing this, these photos crack us up just for the look - no shirt, sauce on his stomach and all over his face, jeans sagging down, diaper hanging out - um... classy.