any reason to keep opened chests?

I just wasted some time tracking down a bug that need not have been
relevant.
There were multiple chests on a square, and after the one on top was
opened,
it remained [squelched] on top of another chest.  It was confusing to see
only
a chest(poison needle) and yet be told there were no traps when trying to
disarm it.  The workaround turned out to be to pick it up and drop it
elsewhere.

The solution is that items in a square should be reordered so that
unsquelched
items are on top of squelched items.  That's also necessary to fix some
other
bugs, so I'll do it eventually.


My question is why even keep an opened chest around?  
Why isn't every chest automatically deleted when it is opened?


Eddie