diff --git a/java/idea-ui/testSrc/com/intellij/facet/AddFacetActionTest.java b/java/idea-ui/testSrc/com/intellij/facet/AddFacetActionTest.java
index c8ef14527a6a..362d19452164 100644
--- a/java/idea-ui/testSrc/com/intellij/facet/AddFacetActionTest.java
+++ b/java/idea-ui/testSrc/com/intellij/facet/AddFacetActionTest.java
@@ -40,7 +40,7 @@ public class AddFacetActionTest extends FacetTestCase {
     myEditorFacade.getModel().addFacetInfo(subInfo);
 
     assertTrue(isVisible(MockFacetType.getInstance()));
-    assertFalse(isVisible(MockSubFacetType.getInstance()));
+    assertTrue(isVisible(MockSubFacetType.getInstance()));
   }
 
   private boolean isVisible(FacetType type) {
diff --git a/java/idea-ui/testSrc/com/intellij/facet/FacetManagerTest.java b/java/idea-ui/testSrc/com/intellij/facet/FacetManagerTest.java
index c42e33a7598c..1270023463d2 100644
--- a/java/idea-ui/testSrc/com/intellij/facet/FacetManagerTest.java
+++ b/java/idea-ui/testSrc/com/intellij/facet/FacetManagerTest.java
@@ -98,6 +98,26 @@ public class FacetManagerTest extends FacetTestCase {
     assertNull(getFacetManager().getFacetByType(MockFacetType.ID));
   }
 
+  public void testTwoSubFacets() {
+    MockFacet mockFacet = addFacet();
+    Facet<?> subFacet1 = addSubFacet(mockFacet, "sub1");
+    Facet<?> subFacet2 = addSubFacet(mockFacet, "sub2");
+    assertSameElements(getFacetManager().getFacetsByType(mockFacet, MockSubFacetType.ID), subFacet1, subFacet2);
+
+    ModifiableFacetModel model = getFacetManager().createModifiableModel();
+    model.removeFacet(subFacet1);
+    commit(model);
+
+    assertSameElements(getFacetManager().getFacetsByType(mockFacet, MockSubFacetType.ID), subFacet2);
+    assertSameElements(getFacetManager().getFacetsByType(MockSubFacetType.ID), subFacet2);
+
+    model = getFacetManager().createModifiableModel();
+    model.removeFacet(mockFacet);
+    commit(model);
+    assertNull(getFacetManager().getFacetByType(MockFacetType.ID));
+    assertNull(getFacetManager().getFacetByType(MockSubFacetType.ID));
+  }
+
   public void testChangeFacetConfiguration() {
     String configData = "data";
     ModifiableFacetModel model = getFacetManager().createModifiableModel();
diff --git a/platform/testFramework/src/com/intellij/facet/mock/MockSubFacetType.java b/platform/testFramework/src/com/intellij/facet/mock/MockSubFacetType.java
index 3104109ec422..ad02af8d30db 100644
--- a/platform/testFramework/src/com/intellij/facet/mock/MockSubFacetType.java
+++ b/platform/testFramework/src/com/intellij/facet/mock/MockSubFacetType.java
@@ -32,6 +32,11 @@ public class MockSubFacetType extends FacetType<Facet, MockFacetConfiguration> {
     return true;
   }
 
+  @Override
+  public boolean isOnlyOneFacetAllowed() {
+    return false;
+  }
+
   public static MockSubFacetType getInstance() {
     return findInstance(MockSubFacetType.class);
   }
diff --git a/platform/workspaceModel/ide/tests/testSrc/com/intellij/workspaceModel/ide/ImlSerializationTest.kt b/platform/workspaceModel/ide/tests/testSrc/com/intellij/workspaceModel/ide/ImlSerializationTest.kt
index 2fe6de8c7855..8025f78f4f2b 100644
--- a/platform/workspaceModel/ide/tests/testSrc/com/intellij/workspaceModel/ide/ImlSerializationTest.kt
+++ b/platform/workspaceModel/ide/tests/testSrc/com/intellij/workspaceModel/ide/ImlSerializationTest.kt
@@ -46,7 +46,7 @@ class ImlSerializationTest {
     checkSerializationSize(bytes, expectedSize, 2_000)
 
     assertTrue("This assertion is a reminder. Have you updated the serializer? Update the serializer version!",
-               26_000 == expectedSize && "v20" == EntityStorageSerializerImpl.SERIALIZER_VERSION)
+               26_000 == expectedSize && "v21" == EntityStorageSerializerImpl.SERIALIZER_VERSION)
   }
 
   @Test
diff --git a/platform/workspaceModel/storage/src/com/intellij/workspaceModel/storage/bridgeEntities/bridgeModelEntities.kt b/platform/workspaceModel/storage/src/com/intellij/workspaceModel/storage/bridgeEntities/bridgeModelEntities.kt
index 0880fccd8658..20b2f98712ad 100644
--- a/platform/workspaceModel/storage/src/com/intellij/workspaceModel/storage/bridgeEntities/bridgeModelEntities.kt
+++ b/platform/workspaceModel/storage/src/com/intellij/workspaceModel/storage/bridgeEntities/bridgeModelEntities.kt
@@ -761,7 +761,7 @@ class FacetEntity(
 
   companion object {
     val moduleDelegate = ManyToOne.NotNull<ModuleEntity, FacetEntity>(ModuleEntity::class.java)
-    val facetDelegate = OneToOneChild.Nullable<FacetEntity, FacetEntity>(FacetEntity::class.java, true)
+    val facetDelegate = ManyToOne.Nullable<FacetEntity, FacetEntity>(FacetEntity::class.java)
   }
 
   override fun persistentId(): FacetId = FacetId(name, facetType, moduleId)
diff --git a/platform/workspaceModel/storage/src/com/intellij/workspaceModel/storage/bridgeEntities/bridgeModelModifiableEntities.kt b/platform/workspaceModel/storage/src/com/intellij/workspaceModel/storage/bridgeEntities/bridgeModelModifiableEntities.kt
index b3db0cf27588..467e0a90cc34 100644
--- a/platform/workspaceModel/storage/src/com/intellij/workspaceModel/storage/bridgeEntities/bridgeModelModifiableEntities.kt
+++ b/platform/workspaceModel/storage/src/com/intellij/workspaceModel/storage/bridgeEntities/bridgeModelModifiableEntities.kt
@@ -256,7 +256,7 @@ class ModifiableFacetEntity : ModifiableWorkspaceEntityBase<FacetEntity>() {
   var moduleId: ModuleId by EntityDataDelegation()
 
   var module: ModuleEntity by MutableManyToOne.NotNull(FacetEntity::class.java, ModuleEntity::class.java)
-  var underlyingFacet: FacetEntity? by MutableOneToOneChild.Nullable(FacetEntity::class.java, FacetEntity::class.java, true)
+  var underlyingFacet: FacetEntity? by MutableManyToOne.Nullable(FacetEntity::class.java, FacetEntity::class.java)
 }
 
 fun WorkspaceEntityStorageDiffBuilder.addFacetEntity(name: String, facetType: String, configurationXmlTag: String?, module: ModuleEntity,
diff --git a/platform/workspaceModel/storage/src/com/intellij/workspaceModel/storage/impl/EntityStorageSerializerImpl.kt b/platform/workspaceModel/storage/src/com/intellij/workspaceModel/storage/impl/EntityStorageSerializerImpl.kt
index 22d6ffaefba6..8e7821fa3cc9 100644
--- a/platform/workspaceModel/storage/src/com/intellij/workspaceModel/storage/impl/EntityStorageSerializerImpl.kt
+++ b/platform/workspaceModel/storage/src/com/intellij/workspaceModel/storage/impl/EntityStorageSerializerImpl.kt
@@ -43,7 +43,7 @@ class EntityStorageSerializerImpl(
   private val versionsContributor: () -> Map<String, String> = { emptyMap() },
 ) : EntityStorageSerializer {
   companion object {
-    const val SERIALIZER_VERSION = "v20"
+    const val SERIALIZER_VERSION = "v21"
   }
 
   private val KRYO_BUFFER_SIZE = 64 * 1024