Looks like the initialize-instance method on string-input-editing-stream was in error (see attached). Mike Watters mike-cl@mwatters.net CLIM-USER> (accept-from-string 'integer "12345" :start 1) 123 INTEGER 5 CLIM-USER> Fix: --- mcclim-cvs/presentation-defs.lisp 2008-05-27 06:15:36.000000000 -0700 +++ mcclim-local/presentation-defs.lisp 2009-01-20 14:02:55.000000000 -0800 @@ -982,7 +982,7 @@ &allow-other-keys) (setf (stream-input-buffer stream) (replace (make-array (- end start) :fill-pointer (- end start)) - string :start1 start :end2 end))) + string :start2 start :end2 end))) (defmethod stream-element-type ((stream string-input-editing-stream)) 'character)