diff --git a/src/main/java/org/olat/course/run/navigation/NavigationHandler.java b/src/main/java/org/olat/course/run/navigation/NavigationHandler.java
index 186f0f37652bb45ae3582a88d88f063ad54424dd..a2b8c7cff6c1cb806928e0474aac9efaa25a29d6 100644
--- a/src/main/java/org/olat/course/run/navigation/NavigationHandler.java
+++ b/src/main/java/org/olat/course/run/navigation/NavigationHandler.java
@@ -446,6 +446,7 @@ public class NavigationHandler implements Disposable {
 				}
 				if (evaluateTree) {
 					treeModel = createTreeModel();
+					reattachExternalTreeModels(treeModel);
 				}
 				
 				if((TreeEvent.COMMAND_TREENODE_OPEN.equals(nodeSubCmd) || TreeEvent.COMMAND_TREENODE_CLOSE.equals(nodeSubCmd)) &&