Another index register buglet, possibly a regression. Two entries should 
be created, but only one appears. This does not occur with TL2013 
context It does occur with the current (20140316) standalone beta.

    \starttext
    Why is there no AB entry in this index with current beta?
    (Not a problem in TL2013.)
    \index{AB}\index{AA}
    \placeindex
    \stoptext

--
Rik