diff --git a/lib/WebGUI/Asset/Wobject/EventManagementSystem.pm b/lib/WebGUI/Asset/Wobject/EventManagementSystem.pm
index 6eb77b922..f96092ae5 100644
--- a/lib/WebGUI/Asset/Wobject/EventManagementSystem.pm
+++ b/lib/WebGUI/Asset/Wobject/EventManagementSystem.pm
@@ -1768,8 +1768,10 @@ sub www_editEvent {
 	my %prereqSets;
 	tie %prereqSets, 'Tie::IxHash';
 	%prereqSets = $self->session->db->buildHash("select prerequisiteId, name from EventManagementSystem_prerequisites order by name");
-	
-	if (scalar(keys(%prereqSets))) {
+	my %prereqMemberships = $self->session->db->buildHash("select prerequisiteId, requiredProductId from EventManagementSystem_prerequisiteEvents where requiredProductId=?",[$pid]);
+	if (scalar(keys(%prereqSets)) && !scalar(keys(%prereqSets))) {
+		#there are some prereq sets entered into the system, and 
+		#this event is not a member of any of them.
 		%prereqSets = (''=>$i18n->echo('select one'),%prereqSets);
 		$f->selectBox(
 			-name=>'prerequisiteId',