Index: lams_central/conf/language/lams/ApplicationResources.properties
===================================================================
diff -u -r865e149fd204483f902dfd91d22f97a181f26773 -r7c9df6d1e46ee42d1084104ce7cf2908b6e273c5
--- lams_central/conf/language/lams/ApplicationResources.properties	(.../ApplicationResources.properties)	(revision 865e149fd204483f902dfd91d22f97a181f26773)
+++ lams_central/conf/language/lams/ApplicationResources.properties	(.../ApplicationResources.properties)	(revision 7c9df6d1e46ee42d1084104ce7cf2908b6e273c5)
@@ -457,7 +457,8 @@
 authoring.fla.branching.end.suffix =end
 authoring.fla.remove.activity.confirm =Are you sure you want to remove the whole branching activity?
 authoring.fla.branching.create.confirm =Transition from this activity already exists.\\nDo you want to create branching here?
-authoring.fla.transition.to.exists.error =Transition to this activity already exists
+authoring.fla.transition.to.exists.error =Transition to this activity already exists.
+authoring.fla.circular.sequence.error =You are not allowed to have a circular sequence.
 authoring.fla.default.annotation.label.title =Label
 authoring.fla.region.fit.button.tooltip =Fit
 authoring.fla.new.folder.button =New
Index: lams_central/conf/language/lams/ApplicationResources_en_AU.properties
===================================================================
diff -u -r865e149fd204483f902dfd91d22f97a181f26773 -r7c9df6d1e46ee42d1084104ce7cf2908b6e273c5
--- lams_central/conf/language/lams/ApplicationResources_en_AU.properties	(.../ApplicationResources_en_AU.properties)	(revision 865e149fd204483f902dfd91d22f97a181f26773)
+++ lams_central/conf/language/lams/ApplicationResources_en_AU.properties	(.../ApplicationResources_en_AU.properties)	(revision 7c9df6d1e46ee42d1084104ce7cf2908b6e273c5)
@@ -457,7 +457,8 @@
 authoring.fla.branching.end.suffix =end
 authoring.fla.remove.activity.confirm =Are you sure you want to remove the whole branching activity?
 authoring.fla.branching.create.confirm =Transition from this activity already exists.\\nDo you want to create branching here?
-authoring.fla.transition.to.exists.error =Transition to this activity already exists
+authoring.fla.transition.to.exists.error =Transition to this activity already exists.
+authoring.fla.circular.sequence.error =You are not allowed to have a circular sequence.
 authoring.fla.default.annotation.label.title =Label
 authoring.fla.region.fit.button.tooltip =Fit
 authoring.fla.new.folder.button =New
Index: lams_central/web/authoring/authoring.jsp
===================================================================
diff -u -r1a1fa63851c7b61e5c875dd3c5ea57027ddad53a -r7c9df6d1e46ee42d1084104ce7cf2908b6e273c5
--- lams_central/web/authoring/authoring.jsp	(.../authoring.jsp)	(revision 1a1fa63851c7b61e5c875dd3c5ea57027ddad53a)
+++ lams_central/web/authoring/authoring.jsp	(.../authoring.jsp)	(revision 7c9df6d1e46ee42d1084104ce7cf2908b6e273c5)
@@ -52,6 +52,7 @@
 				REMOVE_ACTIVITY_CONFIRM : '<fmt:message key="authoring.fla.remove.activity.confirm" />',
 				BRANCHING_CREATE_CONFIRM : '<fmt:message key="authoring.fla.branching.create.confirm" />',
 				TRANSITION_TO_EXISTS_ERROR : '<fmt:message key="authoring.fla.transition.to.exists.error" />',
+				CIRCULAR_SEQUENCE_ERROR : '<fmt:message key="authoring.fla.circular.sequence.error" />',
 				
 				// DecorationLib
 				DEFAULT_ANNOTATION_LABEL_TITLE : '<fmt:message key="authoring.fla.default.annotation.label.title" />',
Index: lams_central/web/includes/javascript/authoring/authoringActivity.js
===================================================================
diff -u -r95c938f934ccea2c2c205e5704c62f80710a73c7 -r7c9df6d1e46ee42d1084104ce7cf2908b6e273c5
--- lams_central/web/includes/javascript/authoring/authoringActivity.js	(.../authoringActivity.js)	(revision 95c938f934ccea2c2c205e5704c62f80710a73c7)
+++ lams_central/web/includes/javascript/authoring/authoringActivity.js	(.../authoringActivity.js)	(revision 7c9df6d1e46ee42d1084104ce7cf2908b6e273c5)
@@ -849,6 +849,23 @@
 			return;
 		}
 		
+		// check for circular sequences
+		var candidate = fromActivity;
+		do {
+			if (candidate.transitions && candidate.transitions.to.length > 0) {
+				candidate = candidate.transitions.to[0].fromActivity;
+			} else if (candidate.branchingActivity && !candidate.isStart) {
+				candidate = candidate.branchingActivity.start;
+			} else {
+				candidate = null;
+			}
+			
+			if (toActivity == candidate) {
+				alert(LABELS.CIRCULAR_SEQUENCE_ERROR);
+				return;
+			}
+		} while (candidate != null);
+		
 		// branchData can be either an existing branch or a title for the new branch
 		var branch = branchData && branchData instanceof ActivityDefs.BranchActivity ? branchData : null,
 			transition = null;