diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/ExperimentPE.java b/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/ExperimentPE.java
index 3629492b2cd29bb59038f27dd9b524f79e2f1c12..8c8c894c0547967e354049a9e88eaf09fec49042 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/ExperimentPE.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/ExperimentPE.java
@@ -478,6 +478,10 @@ public class ExperimentPE implements IEntityPropertiesHolder<ExperimentPropertyP
         return fileName;
     }
 
+    //
+    // IMatchingEntity
+    //
+
     @Transient
     public final String getIdentifier()
     {
diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/MaterialPE.java b/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/MaterialPE.java
index 3d5bc1d53f98af6b72e458534fe66161595fdfbb..7b30f59af12c57c4e647b2bb61b5f7687121d49a 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/MaterialPE.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/MaterialPE.java
@@ -299,6 +299,10 @@ public class MaterialPE implements IIdAndCodeHolder, Comparable<MaterialPE>,
         return AbstractIdAndCodeHolder.compare(this, o);
     }
 
+    //
+    // IMatchingEntity
+    //
+
     @Transient
     public final String getIdentifier()
     {
diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/SamplePE.java b/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/SamplePE.java
index 70efe7fd9bdf329379ce6c68e7d02c20000b315b..1f702eb3e89954b4f1a59890a6d3f61f278e7acb 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/SamplePE.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/generic/shared/dto/SamplePE.java
@@ -453,6 +453,10 @@ public class SamplePE implements IIdAndCodeHolder, Comparable<SamplePE>,
         getSampleProperties().add(property);
     }
 
+    //
+    // IMatchingEntity
+    //
+
     @Transient
     public final String getIdentifier()
     {