find-file strangeness on OS-X

[andrew_certain_gnu]

I'm running Andrew Choi's emacs binary for OS-X, and I'm having a problem 
with find-file.  Normally, if you do C-x C-f RET, emacs looks to see if 
the file in the buffer has changed on disk and asks if you want to reload 
it.  Under OS-X, it just loads the directory.  Is this a bug?  Is it 
configurable?  I'd like to get the normal behavior back.

Thanks.

Andrew

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