Those cabinets really are small but I'll bet that most don't realize their actual function...........
When the trailer is folded up there needs to be something to keep the forward bunk from partially sliding out, into that void that is caused from the front of the trailer jutting out there, on it's own. Those cabinets fit up tight against the bed slide-out and keep in firmly it place. They are as big as they can possibly be and still be able to close the trailer.
They probably could have put some less expensive stops on either side of the window but it certainly would not have been as attractive......handy too. I'm glad that they put the small extra effort into the design
.