diff --git a/modules/global/src/com/haulmont/cuba/core/sys/persistence/CubaEntityFetchGroup.java b/modules/global/src/com/haulmont/cuba/core/sys/persistence/CubaEntityFetchGroup.java
index d36612a941..211554d131 100644
--- a/modules/global/src/com/haulmont/cuba/core/sys/persistence/CubaEntityFetchGroup.java
+++ b/modules/global/src/com/haulmont/cuba/core/sys/persistence/CubaEntityFetchGroup.java
@@ -23,25 +23,9 @@ public class CubaEntityFetchGroup extends EntityFetchGroup {
 
     @Override
     public String onUnfetchedAttribute(FetchGroupTracker entity, String attributeName) {
-        if (entity._persistence_getSession() == null) {
-            throw new IllegalEntityStateException(ExceptionLocalization.buildMessage("cannot_get_unfetched_attribute", new Object[]{entity, attributeName}));
-        }
-        if (attributeName == null) { // occurs on merge
+        if (attributeName == null && entity._persistence_getSession() != null) { // occurs on merge
             return super.onUnfetchedAttribute(entity, null);
         }
-        throw new IllegalEntityStateException("Attribute '" + entity.getClass().getSimpleName() + "." + attributeName +
-                "' is not included into view");
+        throw new IllegalEntityStateException(ExceptionLocalization.buildMessage("cannot_get_unfetched_attribute", new Object[]{entity, attributeName}));
     }
-
-//    @Override
-//    public String onUnfetchedAttributeForSet(FetchGroupTracker entity, String attributeName) {
-//        if (entity instanceof ChangeTracker) {
-//            AttributeChangeListener changeListener =
-//                    (AttributeChangeListener) ((ChangeTracker) entity)._persistence_getPropertyChangeListener();
-//            if (changeListener != null && changeListener.hasChanges())
-//                throw new IllegalStateException("Attribute '" + entity.getClass().getSimpleName() + "." + attributeName +
-//                        "' is unfetched. Unable to refresh the instance because its state has already been changed");
-//        }
-//        return super.onUnfetchedAttributeForSet(entity, attributeName);
-//    }
 }
\ No newline at end of file
diff --git a/modules/gui/src/com/haulmont/cuba/gui/exception/UnfetchedAttributeAccessExceptionHandler.java b/modules/gui/src/com/haulmont/cuba/gui/exception/UnfetchedAttributeAccessExceptionHandler.java
index 66bd2c7232..ffcdb05c2f 100644
--- a/modules/gui/src/com/haulmont/cuba/gui/exception/UnfetchedAttributeAccessExceptionHandler.java
+++ b/modules/gui/src/com/haulmont/cuba/gui/exception/UnfetchedAttributeAccessExceptionHandler.java
@@ -24,12 +24,15 @@ public class UnfetchedAttributeAccessExceptionHandler extends AbstractGenericExc
     private static final Pattern PATTERN = Pattern.compile("at (.+)\\._persistence_get_(.+)\\(");
 
     public UnfetchedAttributeAccessExceptionHandler() {
-        super("org.eclipse.persistence.exceptions.ValidationException");
+        super("com.haulmont.cuba.core.global.IllegalEntityStateException",
+                "org.eclipse.persistence.exceptions.ValidationException");
     }
 
     @Override
     protected boolean canHandle(String className, String message, @Nullable Throwable throwable) {
-        return message.contains("An attempt was made to traverse a relationship using indirection that had a null Session");
+        return className.equals("com.haulmont.cuba.core.global.IllegalEntityStateException")
+                || (className.equals("org.eclipse.persistence.exceptions.ValidationException")
+                    && message.contains("An attempt was made to traverse a relationship using indirection that had a null Session"));
     }
 
     @Override