diff --git a/modules/web/src/com/haulmont/cuba/web/gui/components/AbstractField.java b/modules/web/src/com/haulmont/cuba/web/gui/components/AbstractField.java
index b5768fe7b1..da263b8712 100644
--- a/modules/web/src/com/haulmont/cuba/web/gui/components/AbstractField.java
+++ b/modules/web/src/com/haulmont/cuba/web/gui/components/AbstractField.java
@@ -37,7 +37,7 @@ public class AbstractField<T extends com.itmill.toolkit.ui.Field> extends Abstra
         final ItemWrapper wrapper = new ItemWrapper(datasource, metaClass.getProperties());
         component.setPropertyDataSource(wrapper.getItemProperty(metaProperty));
 
-        component.setRequired(metaProperty.isMandatory());
+        setRequired(metaProperty.isMandatory());
     }
 
     public boolean isRequired() {
diff --git a/modules/web/src/com/haulmont/cuba/web/gui/components/LookupField.java b/modules/web/src/com/haulmont/cuba/web/gui/components/LookupField.java
index 60cc0754d4..03dd175b2b 100644
--- a/modules/web/src/com/haulmont/cuba/web/gui/components/LookupField.java
+++ b/modules/web/src/com/haulmont/cuba/web/gui/components/LookupField.java
@@ -28,4 +28,10 @@ public class LookupField
     public void setLookupDatasource(CollectionDatasource datasource) {
         component.setContainerDataSource(new CollectionDatasourceWrapper(datasource, true));
     }
+
+    @Override
+    public void setRequired(boolean required) {
+        super.setRequired(required);
+        component.setNullSelectionAllowed(!required);
+    }
 }
\ No newline at end of file