diff --git a/rse/plugins/org.eclipse.dstore.core/src/org/eclipse/dstore/core/model/DataElement.java b/rse/plugins/org.eclipse.dstore.core/src/org/eclipse/dstore/core/model/DataElement.java
index a8539bc765c..8a76e071dc6 100644
--- a/rse/plugins/org.eclipse.dstore.core/src/org/eclipse/dstore/core/model/DataElement.java
+++ b/rse/plugins/org.eclipse.dstore.core/src/org/eclipse/dstore/core/model/DataElement.java
@@ -1657,7 +1657,7 @@ public final class DataElement implements IDataElement
 			_isUpdated = false;
 			_isExpanded = true;
 			_buffer = null;
-			_nestedData = null;
+			//_nestedData = null;
 		}
 	}
 	
diff --git a/rse/plugins/org.eclipse.dstore.core/src/org/eclipse/dstore/core/model/DataStore.java b/rse/plugins/org.eclipse.dstore.core/src/org/eclipse/dstore/core/model/DataStore.java
index 42979dcfad8..0df1cfbb9c5 100644
--- a/rse/plugins/org.eclipse.dstore.core/src/org/eclipse/dstore/core/model/DataStore.java
+++ b/rse/plugins/org.eclipse.dstore.core/src/org/eclipse/dstore/core/model/DataStore.java
@@ -1269,7 +1269,10 @@ public final class DataStore
 			parent.addNestedData(newObject, false);
 		}
 
-		_hashMap.put(id, newObject);
+		synchronized(_hashMap)
+		{
+			_hashMap.put(id, newObject);
+		}
 		
 		if (_autoRefresh)
 			refresh(parent);