diff --git a/rs-tests.rkt b/rs-tests.rkt
index d25b355..2c0ae5b 100644
--- a/rs-tests.rkt
+++ b/rs-tests.rkt
@@ -81,4 +81,5 @@
                    (list (set 'y) (set 'y 'z))
                    (list (set 'z) (set))
                    (list (set) (set))
-                   (list (set 'z) (set))))))
+                   (list (set 'z) (set))
+                   (list (set) (set))))))
diff --git a/rs.rkt b/rs.rkt
index 7b6a855..03a8462 100644
--- a/rs.rkt
+++ b/rs.rkt
@@ -178,13 +178,15 @@
 ;;; sequence.  The output is a list of pairs of lists in which the
 ;;; first element is the current context and the second element is the
 ;;; result of the application of reactions to the previous state.  The
-;;; interactive process stops when there are no more contexts left.
+;;; interactive process stops one step after the end of the context
+;;; sequence, to show the effect of the last context.
 (define (build-interactive-process rs contexts)
-  (let ([dyn (dynamics rs)])
+  (let ([dyn (dynamics rs)]
+        [padded-contexts (append contexts (list (set)))])
     (for/fold ([proc '()]
-               [st (state (set) contexts)]
+               [st (state (set) padded-contexts)]
                #:result (reverse proc))
-              ([c contexts])
+              ([c padded-contexts])
       (values
        (cons (match st
                [(state res ctx)