--- loncom/interface/loncommon.pm	2017/05/23 03:07:36	1.1280
+++ loncom/interface/loncommon.pm	2017/06/26 01:34:32	1.1281
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # a pile of common routines
 #
-# $Id: loncommon.pm,v 1.1280 2017/05/23 03:07:36 raeburn Exp $
+# $Id: loncommon.pm,v 1.1281 2017/06/26 01:34:32 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -5187,13 +5187,19 @@ sub get_blocks {
                 my $end = $start + $env{'course.'.$cdom.'_'.$cnum.'.timerinterval.'.$timersymb}; 
                 if ($start && $end) {
                     if (($start <= time) && ($end >= time)) {
-                        unless (grep(/^\Q$block\E$/,@blockers)) {
-                            push(@blockers,$block);
-                            $triggered{$block} = {
-                                                   start => $start,
-                                                   end   => $end,
-                                                   type  => $type,
-                                                 };
+                        if (ref($commblocks{$block}) eq 'HASH') {
+                            if (ref($commblocks{$block}{'blocks'}) eq 'HASH') {
+                                if ($commblocks{$block}{'blocks'}{$activity} eq 'on') {
+                                    unless(grep(/^\Q$block\E$/,@blockers)) {
+                                        push(@blockers,$block);
+                                        $triggered{$block} = {
+                                                               start => $start,
+                                                               end   => $end,
+                                                               type  => $type,
+                                                             };
+                                    }
+                                }
+                            }
                         }
                     }
                 }