--- loncom/interface/lonhelper.pm	2005/10/11 22:05:20	1.122
+++ loncom/interface/lonhelper.pm	2005/10/17 18:20:59	1.123
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # .helper XML handler to implement the LON-CAPA helper
 #
-# $Id: lonhelper.pm,v 1.122 2005/10/11 22:05:20 albertel Exp $
+# $Id: lonhelper.pm,v 1.123 2005/10/17 18:20:59 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -2189,6 +2189,10 @@ selection. Defaults to false.
 If true, only active students and course personnel will be
 shown. Defaults to false.
 
+=item * B<emptyallowed>:
+
+If true, the selection of no users is allowed. Defaults to false.
+
 =back
 
 =cut
@@ -2224,6 +2228,7 @@ sub start_student {
     if (defined($token->[2]{'nextstate'})) {
         $paramHash->{NEXTSTATE} = $token->[2]{'nextstate'};
     }
+    $paramHash->{'emptyallowed'} = $token->[2]{'emptyallowed'};
     
 }    
 
@@ -2485,9 +2490,14 @@ sub postprocess {
     my $self = shift;
 
     my $result = $env{'form.' . $self->{'variable'} . '.forminput'};
-    if (!$result) {
-        $self->{ERROR_MSG} = 
-	    &mt('You must choose at least one student to continue.');
+    if (!$result && !$self->{'emptyallowed'}) {
+	if ($self->{'coursepersonnel'}) {
+	    $self->{ERROR_MSG} = 
+		&mt('You must choose at least one user to continue.');
+	} else {
+	    $self->{ERROR_MSG} = 
+		&mt('You must choose at least one student to continue.');
+	}
         return 0;
     }