Update dynamics.ml

close #87

Author: jkrivine

pattern/dynamics.ml

@@ -380,8 +380,8 @@ let diff pos m0 m1 label_opt env =
 										| (Node.BND, Node.BND) | (Node.TYPE _, Node.BND) -> (*connected -> connected*)
 												begin
 													let opt, opt' = (Mixture.follow (id, site_id) m0, Mixture.follow (id, site_id) m1) in
-													if opt = opt' then (inst,idmap) (*no change to be made*)
-													else
+													(*if opt = opt' then (inst,idmap)*) (*issue87*)
+													(*else*)
 														match (opt, opt') with
 														| (None, Some (id1', i1')) -> (*sub-case: semi-link -> connected*)
 															(*warning*)
@@ -409,6 +409,7 @@ let diff pos m0 m1 label_opt env =
 
 														| (Some (id1, i1), Some (id1', i1')) -> (*sub-case: connected -> connected*)
 																(*warning*)
+																let idmap = add_map (KEPT id) (site_id,1) idmap in
 																let site = Environment.site_of_id (Mixture.name ag) site_id env in
 																let _ =
 																	warning