Index: perllib/Polymake/Core/PlainFile.pm
===================================================================
--- perllib/Polymake/Core/PlainFile.pm	(revision 9931)
+++ perllib/Polymake/Core/PlainFile.pm	(revision 10207)
@@ -203,8 +203,11 @@
 	    if ($@) {
 	       report_parse_error($self, "error reading property '$prop_name'");
 	    }
+         } elsif ($Shell->interactive) {
+            consume_unknown_property($prop_name, $value, $object);
 	 } else {
-	    consume_unknown_property($prop_name, $value, $object);
+            report_error($self, "unknown property '$prop_name'");
+            $self->unknown_seen=1;
 	 }
 
       } else {
@@ -225,7 +228,7 @@
 ***************************************************************************
 You can convert the unknown sections to attachments and/or valid properties
 if you load the file $name in the interactive shell or by executing
-polymake --touch $file
+polymake --touch $name
 ***************************************************************************
 .
       }
@@ -243,13 +246,6 @@
 #################################################################################
 sub consume_unknown_property {
    my ($prop_name, $value, $object)=@_;
-
-   unless ($Shell->interactive) {
-      report_error($self, "unknown property '$prop_name'");
-      $self->unknown_seen=1;
-      return;
-   }
-
    (my $show_value=$value) =~ s/\A((?:^.*\n){3})^(?s:.+)\Z/$1...\n/m;
 
    local_sub($Shell->try_completion,
@@ -263,10 +259,10 @@
 		   if (defined($obj_type)) {
 		      if (defined (my $proto=eval { $User::application->eval_type($obj_type) })) {
 			 push @{$self->completion_words},
-                              map { "$obj_type\::$_" } $self->try_property_completion($word, $proto, $prefix);
+                              map { "$obj_type\::$_" } Shell::try_property_completion($proto, $prefix);
 		      }
 		   } else {
-		      push @{$self->completion_words}, $self->try_property_completion($word, $object->type, $prefix);
+                      push @{$self->completion_words}, Shell::try_property_completion($object->type, $prefix);
 		   }
 		}
 	     });