Index: lams_common/src/java/org/lamsfoundation/lams/dbupdates/patch20180201.sql
===================================================================
diff -u
--- lams_common/src/java/org/lamsfoundation/lams/dbupdates/patch20180201.sql	(revision 0)
+++ lams_common/src/java/org/lamsfoundation/lams/dbupdates/patch20180201.sql	(revision d15ad2104997c36ac5ccb243c2d3db1d42e60f33)
@@ -0,0 +1,9 @@
+SET AUTOCOMMIT = 0;
+set FOREIGN_KEY_CHECKS = 0;
+ 
+--  LDEV-4507 Make sure that duplicate groups are not created
+ALTER TABLE lams_group ADD UNIQUE KEY UQ_lams_group_1 (grouping_id, order_id);
+ 
+COMMIT;
+SET AUTOCOMMIT = 1;
+set FOREIGN_KEY_CHECKS = 1;
Index: lams_common/src/java/org/lamsfoundation/lams/learningdesign/Group.java
===================================================================
diff -u -refd67298c7f0ea03a8fc9d670329812589db742a -rd15ad2104997c36ac5ccb243c2d3db1d42e60f33
--- lams_common/src/java/org/lamsfoundation/lams/learningdesign/Group.java	(.../Group.java)	(revision efd67298c7f0ea03a8fc9d670329812589db742a)
+++ lams_common/src/java/org/lamsfoundation/lams/learningdesign/Group.java	(.../Group.java)	(revision d15ad2104997c36ac5ccb243c2d3db1d42e60f33)
@@ -37,7 +37,7 @@
 
 public class Group implements Serializable, Nullable, Comparable<Group> {
 
-    public final static int STAFF_GROUP_ORDER_ID = 1;
+    public final static int STAFF_GROUP_ORDER_ID = 2;
     public final static String NAME_OF_STAFF_GROUP = "Staff Group";
 
     /** identifier field */
Index: lams_learning/src/java/org/lamsfoundation/lams/learning/service/ICoreLearnerService.java
===================================================================
diff -u -r16593058f78a135e25dae055f0fc16c4bed4da42 -rd15ad2104997c36ac5ccb243c2d3db1d42e60f33
--- lams_learning/src/java/org/lamsfoundation/lams/learning/service/ICoreLearnerService.java	(.../ICoreLearnerService.java)	(revision 16593058f78a135e25dae055f0fc16c4bed4da42)
+++ lams_learning/src/java/org/lamsfoundation/lams/learning/service/ICoreLearnerService.java	(.../ICoreLearnerService.java)	(revision d15ad2104997c36ac5ccb243c2d3db1d42e60f33)
@@ -229,7 +229,7 @@
      * @return the maximum number of learners per group;<code>null</code> if the requirement for equal number of
      *         learners in groups was not set
      */
-    Integer calculateMaxNumberOfLearnersPerGroup(Long lessonId, Grouping grouping);
+    Integer calculateMaxNumberOfLearnersPerGroup(Long lessonId, Long groupingId);
 
     Grouping getGrouping(Long groupingId);
 
Index: lams_learning/src/java/org/lamsfoundation/lams/learning/service/LearnerService.java
===================================================================
diff -u -r60355e9a91260c605e1a55e1f2329dd69fea08b9 -rd15ad2104997c36ac5ccb243c2d3db1d42e60f33
--- lams_learning/src/java/org/lamsfoundation/lams/learning/service/LearnerService.java	(.../LearnerService.java)	(revision 60355e9a91260c605e1a55e1f2329dd69fea08b9)
+++ lams_learning/src/java/org/lamsfoundation/lams/learning/service/LearnerService.java	(.../LearnerService.java)	(revision d15ad2104997c36ac5ccb243c2d3db1d42e60f33)
@@ -890,8 +890,8 @@
     public Lesson getLessonByActivity(Activity activity) {
 	Lesson lesson = lessonDAO.getLessonForActivity(activity.getActivityId());
 	if (lesson == null) {
-	    LearnerService.log
-		    .warn("Tried to get lesson id for a non-lesson based activity. An error is likely to be thrown soon. Activity was "
+	    LearnerService.log.warn(
+		    "Tried to get lesson id for a non-lesson based activity. An error is likely to be thrown soon. Activity was "
 			    + activity);
 	}
 	return lesson;
@@ -1031,8 +1031,8 @@
 		    SequenceActivity.class);
 	} else {
 	    if (LearnerService.log.isDebugEnabled()) {
-		LearnerService.log
-			.debug("No branches match and no default branch exists. Uable to allocate learner to a branch for the branching activity"
+		LearnerService.log.debug(
+			"No branches match and no default branch exists. Uable to allocate learner to a branch for the branching activity"
 				+ branchingActivity.getActivityId() + ":" + branchingActivity.getTitle()
 				+ " for learner " + learner.getUserId() + ":" + learner.getLogin());
 	    }
@@ -1241,11 +1241,11 @@
      * {@inheritDoc}
      */
     @Override
-    public Integer calculateMaxNumberOfLearnersPerGroup(Long lessonId, Grouping grouping) {
-	Lesson lesson = getLesson(lessonId);
+    public Integer calculateMaxNumberOfLearnersPerGroup(Long lessonId, Long groupingId) {
+	LearnerChoiceGrouping grouping = (LearnerChoiceGrouping) getGrouping(groupingId);
 	LearnerChoiceGrouping learnerChoiceGrouping = (LearnerChoiceGrouping) grouping;
 	Integer maxNumberOfLearnersPerGroup = null;
-	int learnerCount = lesson.getAllLearners().size();
+	int learnerCount = lessonService.getCountLessonLearners(lessonId, null);
 	int groupCount = grouping.getGroups().size();
 	if (learnerChoiceGrouping.getLearnersPerGroup() == null) {
 	    if (groupCount == 0) {
Index: lams_learning/src/java/org/lamsfoundation/lams/learning/web/action/GroupingAction.java
===================================================================
diff -u -r75496fa1baab1302fe097cce2183029e19285ebf -rd15ad2104997c36ac5ccb243c2d3db1d42e60f33
--- lams_learning/src/java/org/lamsfoundation/lams/learning/web/action/GroupingAction.java	(.../GroupingAction.java)	(revision 75496fa1baab1302fe097cce2183029e19285ebf)
+++ lams_learning/src/java/org/lamsfoundation/lams/learning/web/action/GroupingAction.java	(.../GroupingAction.java)	(revision d15ad2104997c36ac5ccb243c2d3db1d42e60f33)
@@ -153,11 +153,10 @@
 	// forward to group choosing page
 	if (((GroupingActivity) activity).getCreateGrouping().isLearnerChoiceGrouping()) {
 	    Long groupingId = ((GroupingActivity) activity).getCreateGrouping().getGroupingId();
-
-	    LearnerChoiceGrouping grouping = (LearnerChoiceGrouping) learnerService.getGrouping(groupingId);
 	    Integer maxNumberOfLeaernersPerGroup = learnerService.calculateMaxNumberOfLearnersPerGroup(lessonId,
-		    grouping);
+		    groupingId);
 
+	    LearnerChoiceGrouping grouping = (LearnerChoiceGrouping) learnerService.getGrouping(groupingId);
 	    prepareGroupData(request);
 	    request.setAttribute(GroupingAction.MAX_LEARNERS_PER_GROUP, maxNumberOfLeaernersPerGroup);
 	    request.setAttribute(GroupingAction.LOCAL_FILES, Boolean.FALSE);
@@ -236,7 +235,6 @@
      *
      * @param request
      */
-    @SuppressWarnings("unchecked")
     private void prepareGroupData(HttpServletRequest request) {
 
 	ICoreLearnerService learnerService = LearnerServiceProxy.getLearnerService(getServlet().getServletContext());
@@ -287,9 +285,9 @@
 	}
 	Long groupingId = ((GroupingActivity) activity).getCreateGrouping().getGroupingId();
 
+	Integer maxNumberOfLeaernersPerGroup = learnerService.calculateMaxNumberOfLearnersPerGroup(lessonId,
+		groupingId);
 	LearnerChoiceGrouping grouping = (LearnerChoiceGrouping) learnerService.getGrouping(groupingId);
-	Integer maxNumberOfLeaernersPerGroup = learnerService.calculateMaxNumberOfLearnersPerGroup(lessonId, grouping);
-
 	prepareGroupData(request);
 	request.setAttribute(GroupingAction.MAX_LEARNERS_PER_GROUP, maxNumberOfLeaernersPerGroup);
 	request.setAttribute(GroupingAction.LOCAL_FILES, Boolean.FALSE);