Box.net has dynload=false, which means that on each request the whole tree is retrieved and returned to filepicker.
It works ok in JS filepicker because it caches the tree and when user selects a folder no request to server is sent
But in non-JS filepicker the request for each subfolder is sent but boxclient::getfiletree ignores argument $path.
Also I receive a warning:
I traced it back and noticed that boxclient::buildtree returns an array in 'path' attribute instead of a string