From a20a1c95067b40cb16189d7d5c8baed33210765d Mon Sep 17 00:00:00 2001
From: tHerrmann <t.herrmann@alkacon.com>
Date: Wed, 15 Feb 2017 14:16:23 +0100
Subject: [PATCH] Avoiding unsupported operation exceptions on empty lists.

---
 src/org/opencms/ade/containerpage/CmsModelGroupHelper.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/org/opencms/ade/containerpage/CmsModelGroupHelper.java b/src/org/opencms/ade/containerpage/CmsModelGroupHelper.java
index 325dc4ecbf8..dc4140f78fb 100644
--- a/src/org/opencms/ade/containerpage/CmsModelGroupHelper.java
+++ b/src/org/opencms/ade/containerpage/CmsModelGroupHelper.java
@@ -897,7 +897,7 @@ private List<CmsContainerBean> readModelContainers(
         if (containerByParent.containsKey(modelInstanceId)) {
             modelContainers = collectModelStructure(modelInstanceId, localInstanceId, containerByParent);
         } else {
-            modelContainers = Collections.emptyList();
+            modelContainers = new ArrayList<CmsContainerBean>();
         }
         return modelContainers;
     }