diff --git a/com.avaloq.tools.ddk.xtext/src/com/avaloq/tools/ddk/xtext/resource/persistence/DirectLinkingResourceStorageLoadable.java b/com.avaloq.tools.ddk.xtext/src/com/avaloq/tools/ddk/xtext/resource/persistence/DirectLinkingResourceStorageLoadable.java
index 313de97589..2c7ef9f77d 100644
--- a/com.avaloq.tools.ddk.xtext/src/com/avaloq/tools/ddk/xtext/resource/persistence/DirectLinkingResourceStorageLoadable.java
+++ b/com.avaloq.tools.ddk.xtext/src/com/avaloq/tools/ddk/xtext/resource/persistence/DirectLinkingResourceStorageLoadable.java
@@ -65,16 +65,10 @@ public class DirectLinkingResourceStorageLoadable extends ResourceStorageLoadabl
    * - count the number of EObjects added to the Resource
    */
   private final class EObjectInputStreamExtension extends BinaryResourceImpl.EObjectInputStream {
-    private int objectCount;
-
     private EObjectInputStreamExtension(final InputStream inputStream, final Map<?, ?> options) throws IOException {
       super(inputStream, options);
     }
 
-    public int eObjectCount() {
-      return objectCount;
-    }
-
     @Override
     public int readCompressedInt() throws IOException {
       // HACK! null resource set, to avoid usage of resourceSet's package registry
@@ -86,7 +80,6 @@ public int readCompressedInt() throws IOException {
     public InternalEObject loadEObject() throws IOException {
       final InternalEObject result = super.loadEObject();
       handleLoadEObject(result, this);
-      objectCount++;
       return result;
     }
 
@@ -146,8 +139,6 @@ public void loadResource(final Resource resource) throws IOException {
 
   private ResourceLoadMode mode;
 
-  private int eObjectCount;
-
   public DirectLinkingResourceStorageLoadable(final InputStream in, final boolean loadNodeModel, final boolean splitContents, final ITraceSet traceSet) {
     super(in, loadNodeModel);
     this.loadNodeModel = loadNodeModel;
@@ -271,7 +262,7 @@ protected void loadEntries(final StorageAwareResource resource, final ZipInputSt
       case SKIP:
         break;
       case PROXY:
-        ProxyCompositeNode.installProxyNodeModel(resource, eObjectCount);
+        ProxyCompositeNode.installProxyNodeModel(resource);
         break;
       case LOAD:
         readNodeModel(resource, new NonLockingBufferInputStream(zipIn), content);
@@ -379,7 +370,6 @@ private Deque<EObject> readMappedEObjects(final DirectLinkingEObjectInputStream
   protected void readContents(final StorageAwareResource resource, final InputStream inputStream) throws IOException {
     final EObjectInputStreamExtension in = new EObjectInputStreamExtension(inputStream, Collections.emptyMap());
     in.loadResource(resource);
-    eObjectCount = in.eObjectCount();
   }
 
 }
diff --git a/com.avaloq.tools.ddk.xtext/src/com/avaloq/tools/ddk/xtext/resource/persistence/ProxyCompositeNode.java b/com.avaloq.tools.ddk.xtext/src/com/avaloq/tools/ddk/xtext/resource/persistence/ProxyCompositeNode.java
index 229e821039..4329809e99 100644
--- a/com.avaloq.tools.ddk.xtext/src/com/avaloq/tools/ddk/xtext/resource/persistence/ProxyCompositeNode.java
+++ b/com.avaloq.tools.ddk.xtext/src/com/avaloq/tools/ddk/xtext/resource/persistence/ProxyCompositeNode.java
@@ -23,8 +23,6 @@
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.InternalEObject;
 import org.eclipse.emf.ecore.resource.Resource;
-import org.eclipse.emf.ecore.util.EContentsEList.FeatureIterator;
-import org.eclipse.emf.ecore.util.EContentsEList.Filterable;
 import org.eclipse.emf.ecore.util.EcoreUtil;
 import org.eclipse.xtext.nodemodel.BidiIterable;
 import org.eclipse.xtext.nodemodel.BidiTreeIterable;
@@ -37,6 +35,7 @@
 import org.eclipse.xtext.nodemodel.util.NodeModelUtils;
 import org.eclipse.xtext.nodemodel.util.NodeTreeIterator;
 import org.eclipse.xtext.nodemodel.util.ReversedBidiTreeIterable;
+import org.eclipse.xtext.parser.IParseResult;
 import org.eclipse.xtext.parser.ParseResult;
 import org.eclipse.xtext.resource.XtextResource;
 import org.eclipse.xtext.resource.persistence.IResourceStorageFacade;
@@ -53,7 +52,7 @@
  * To conserve memory this class implements the primary interfaces rather than extending an implementation like
  * {@link org.eclipse.xtext.nodemodel.impl.CompositeNodeWithSemanticElement}.
  */
-class ProxyCompositeNode implements ICompositeNode, BidiTreeIterable<INode>, Adapter {
+public class ProxyCompositeNode implements ICompositeNode, BidiTreeIterable<INode>, Adapter {
 
   /** The root node proxy stores the original EObject ID map so that it can be used when installing the real node model. */
   private List<EObject> idToEObjectMap;
@@ -69,48 +68,34 @@ class ProxyCompositeNode implements ICompositeNode, BidiTreeIterable<INode>, Ada
    *
    * @param resource
    *          resource, must not be {@code null}
-   * @param expectedEObjectCount
-   *          the expected EObject count of the resource
    */
-  static void installProxyNodeModel(final Resource resource, final int expectedEObjectCount) {
+  static void installProxyNodeModel(final Resource resource) {
     if (resource.getContents().isEmpty()) {
       return;
     }
 
-    EObject root = resource.getContents().get(0);
-
-    ProxyCompositeNode rootNode = installProxyNodeModel(root);
-    rootNode.idToEObjectMap = new ArrayList<>(expectedEObjectCount);
-    fillIdToEObjectMap(root, rootNode.idToEObjectMap);
-
-    if (resource instanceof XtextResource) {
-      ((XtextResource) resource).setParseResult(new ParseResult(root, rootNode, false));
+    if (resource instanceof XtextResource xtextResource) {
+      EObject root = resource.getContents().get(0);
+      xtextResource.setParseResult(new ParseResult(root, createRootNode(root), false));
     }
   }
 
-  private static ProxyCompositeNode installProxyNodeModel(final EObject eObject) {
+  private static ProxyCompositeNode createRootNode(final EObject eObject) {
     ProxyCompositeNode result = new ProxyCompositeNode();
     eObject.eAdapters().add(result);
     return result;
   }
 
-  private static void fillIdToEObjectMap(final EObject eObject, final List<EObject> map) {
-    map.add(eObject);
-
-    FeatureIterator<EObject> iterator = (FeatureIterator<EObject>) eObject.eContents().iterator();
-    if (iterator instanceof Filterable filterable) {
-      filterable.filter(f -> !f.isTransient());
-      for (FeatureIterator<EObject> it = iterator; it.hasNext();) {
-        fillIdToEObjectMap(it.next(), map);
-      }
-    } else {
-      // post-filter the iterator, which is extra work
-      for (FeatureIterator<EObject> it = iterator; it.hasNext();) {
-        EObject child = it.next();
-        if (!it.feature().isTransient()) {
-          fillIdToEObjectMap(child, map);
-        }
-      }
+  /**
+   * Fill id to EOject map.
+   *
+   * @param parseResult
+   *          the {@link IParseResult}
+   */
+  public static void fillIdToEObjectMap(final IParseResult parseResult) {
+    if (parseResult.getRootNode() instanceof ProxyCompositeNode rootNode && rootNode.idToEObjectMap == null) {
+      rootNode.idToEObjectMap = new ArrayList<>();
+      ProxyAwareSerializationConversionContext.fillIdToEObjectMap(parseResult.getRootASTElement(), rootNode.idToEObjectMap);
     }
   }