diff --git a/PROMS/VEPROMS User Interface/dlgManageSecurity.cs b/PROMS/VEPROMS User Interface/dlgManageSecurity.cs
index e8fce203..c398fc40 100644
--- a/PROMS/VEPROMS User Interface/dlgManageSecurity.cs	
+++ b/PROMS/VEPROMS User Interface/dlgManageSecurity.cs	
@@ -418,7 +418,7 @@ namespace VEPROMS
 			cmMembers.Items.Clear();
 			lstGroups.SelectedIndex = -1;
 
-			if (e.Button == MouseButtons.Right)
+			if (e.Button == MouseButtons.Right && lstUsers.SelectedIndex > -1)
 			{
 				int k = lstGroups.IndexFromPoint(e.Location);
 				if (k >= 0)