Index: lams_common/src/java/org/lamsfoundation/lams/lesson/service/LessonService.java
===================================================================
diff -u -r5c85cfda092e7e27ab618e86469821a4587f3849 -r8bc8d173f84ddf9333719585a3ddfd7a676f28be
--- lams_common/src/java/org/lamsfoundation/lams/lesson/service/LessonService.java	(.../LessonService.java)	(revision 5c85cfda092e7e27ab618e86469821a4587f3849)
+++ lams_common/src/java/org/lamsfoundation/lams/lesson/service/LessonService.java	(.../LessonService.java)	(revision 8bc8d173f84ddf9333719585a3ddfd7a676f28be)
@@ -237,7 +237,9 @@
      */
   	public void performGrouping(Grouping grouping, String groupName, List learners) throws LessonServiceException {
   		
-		if ( grouping != null && grouping.isChosenGrouping() ) {
+		if ( grouping != null ) {
+			// Ensure we have a real grouping object, not just a CGLIB version (LDEV-1817)
+			grouping = groupingDAO.getGroupingById(grouping.getGroupingId());
         	Grouper grouper = grouping.getGrouper();
         	if ( grouper != null ) {
         		grouper.setCommonMessageService(messageService);
@@ -248,10 +250,6 @@
         		}
         		groupingDAO.update(grouping);
         	}
-		} else {
-			String error = "The method performChosenGrouping supports only grouping methods where the supplied list should be used as a single group (currently only ChosenGrouping). Called with wrong grouper "+grouping;
-			log.error(error);
-			throw new LessonServiceException(error);
 		}
   	}
     
Index: lams_learning/src/java/org/lamsfoundation/lams/learning/service/LearnerService.java
===================================================================
diff -u -r5dafa6ad3cc7b265266420295fe76fb6c8d7a9fb -r8bc8d173f84ddf9333719585a3ddfd7a676f28be
--- lams_learning/src/java/org/lamsfoundation/lams/learning/service/LearnerService.java	(.../LearnerService.java)	(revision 5dafa6ad3cc7b265266420295fe76fb6c8d7a9fb)
+++ lams_learning/src/java/org/lamsfoundation/lams/learning/service/LearnerService.java	(.../LearnerService.java)	(revision 8bc8d173f84ddf9333719585a3ddfd7a676f28be)
@@ -49,7 +49,6 @@
 import org.lamsfoundation.lams.learningdesign.Group;
 import org.lamsfoundation.lams.learningdesign.Grouping;
 import org.lamsfoundation.lams.learningdesign.GroupingActivity;
-import org.lamsfoundation.lams.learningdesign.LearningDesign;
 import org.lamsfoundation.lams.learningdesign.SequenceActivity;
 import org.lamsfoundation.lams.learningdesign.ToolActivity;
 import org.lamsfoundation.lams.learningdesign.ToolBranchingActivity;
@@ -612,10 +611,24 @@
 		if ( lesson.isPreviewLesson() ) {
 			ArrayList<User> learnerList = new ArrayList<User>();
 			learnerList.add(learner);
-			if ( group != null && group.getGroupId() != null )
-				lessonService.performGrouping(grouping, group!=null?group.getGroupId():null, learnerList);
-			else 
-				lessonService.performGrouping(grouping, group.getGroupName(), learnerList);
+			if ( group != null ) {
+				if ( group.getGroupId() != null )
+					lessonService.performGrouping(grouping, group.getGroupId(), learnerList);
+				else 
+					lessonService.performGrouping(grouping, group.getGroupName(), learnerList);
+			} else {
+				if ( grouping.getGroups().size() > 0 ) {
+					// if any group exists, put them in there.
+					Group aGroup = (Group)grouping.getGroups().iterator().next();
+					if ( aGroup.getGroupId() != null )
+						lessonService.performGrouping(grouping, aGroup.getGroupId(), learnerList);
+					else 
+						lessonService.performGrouping(grouping, aGroup.getGroupName(), learnerList);
+				} else {
+					// just create a group and stick the user in there!
+					lessonService.performGrouping(grouping, (String)null, learnerList);
+				}
+			}
 			groupingDone = true;
 		}
 		return groupingDone;
@@ -993,8 +1006,14 @@
 					}
 				}
 				
-			// if no groups exist, then create one and assign it to the branch.
-    		} else {
+			// if no matching groups exist (just to Define in Monitor), then create one and assign it to the branch. 
+			// if it is a chosen grouping, make sure we allow it to go over the normal number of groups (the real groups will exist
+			// but it too hard to reuse them.)
+			} else {
+    			if ( grouping.isChosenGrouping() && grouping.getMaxNumberOfGroups() != null ) {
+   					grouping.setMaxNumberOfGroups(null); 
+    			}
+
 				Group group = lessonService.createGroup(grouping, selectedBranch.getTitle());
 				group.allocateBranchToGroup(null, selectedBranch, branchingActivity);
 				if ( ! forceGrouping(lesson, grouping, group, learner) ) {
Index: lams_learning/src/java/org/lamsfoundation/lams/learning/web/action/LoadToolActivityAction.java
===================================================================
diff -u -r5863520d75343b47f77b05ad3bd7045a9a39af49 -r8bc8d173f84ddf9333719585a3ddfd7a676f28be
--- lams_learning/src/java/org/lamsfoundation/lams/learning/web/action/LoadToolActivityAction.java	(.../LoadToolActivityAction.java)	(revision 5863520d75343b47f77b05ad3bd7045a9a39af49)
+++ lams_learning/src/java/org/lamsfoundation/lams/learning/web/action/LoadToolActivityAction.java	(.../LoadToolActivityAction.java)	(revision 8bc8d173f84ddf9333719585a3ddfd7a676f28be)
@@ -59,6 +59,7 @@
 
 	public static final String DEFINE_LATER = "previewDefineLater";
 	public static final String PARAM_ACTIVITY_URL = "activityURL";
+	public static final String PARAM_IS_BRANCHING = "isBranching";
 
 	/**
 	 * Gets an activity from the request (attribute) and forwards onto a
@@ -88,6 +89,7 @@
 				// preview define later
 				request.setAttribute(AttributeNames.PARAM_TITLE, activity.getTitle());
 				request.setAttribute(PARAM_ACTIVITY_URL, url);
+				request.setAttribute(PARAM_IS_BRANCHING, activity.isBranchingActivity());
 				return mapping.findForward("previewDefineLater");
 			} else {
 				// normal case