diff --git a/platform/lang-impl/src/com/intellij/ide/scratch/ScratchFileType.java b/platform/lang-impl/src/com/intellij/ide/scratch/ScratchFileType.java
index d3232a428452..abac965ebed4 100644
--- a/platform/lang-impl/src/com/intellij/ide/scratch/ScratchFileType.java
+++ b/platform/lang-impl/src/com/intellij/ide/scratch/ScratchFileType.java
@@ -34,7 +34,7 @@ public class ScratchFileType extends LanguageFileType implements FileTypeIdentif
   public static final LanguageFileType INSTANCE = new ScratchFileType();
 
   ScratchFileType() {
-    super(PlainTextLanguage.INSTANCE);
+    super(PlainTextLanguage.INSTANCE, true);
   }
 
   @Override
diff --git a/platform/platform-resources/src/META-INF/LangExtensions.xml b/platform/platform-resources/src/META-INF/LangExtensions.xml
index fcb8dd10379c..5304aaf5469b 100644
--- a/platform/platform-resources/src/META-INF/LangExtensions.xml
+++ b/platform/platform-resources/src/META-INF/LangExtensions.xml
@@ -362,7 +362,7 @@
     <projectViewPane implementation="com.intellij.ide.scratch.ScratchProjectViewPane"/>
     <treeStructureProvider implementation="com.intellij.ide.scratch.ScratchProjectViewPane$MyStructureProvider" order="last"/>
 
-    <fileType name="Scratch" language="TEXT" implementationClass="com.intellij.ide.scratch.ScratchFileType" fieldName="INSTANCE"/>
+    <fileType name="Scratch" implementationClass="com.intellij.ide.scratch.ScratchFileType" fieldName="INSTANCE"/>
     <navbar implementation="com.intellij.ide.scratch.ScratchFileServiceImpl$NavBarExtension"/>
     <lang.substitutor language="TEXT" implementationClass="com.intellij.ide.scratch.ScratchFileServiceImpl$Substitutor" order="first"/>
     <nonProjectFileWritingAccessExtension implementation="com.intellij.ide.scratch.ScratchFileServiceImpl$AccessExtension"/>
diff --git a/platform/platform-tests/testSrc/com/intellij/openapi/fileTypes/impl/FileTypesTest.java b/platform/platform-tests/testSrc/com/intellij/openapi/fileTypes/impl/FileTypesTest.java
index 9260020f8203..ae4e521e603b 100644
--- a/platform/platform-tests/testSrc/com/intellij/openapi/fileTypes/impl/FileTypesTest.java
+++ b/platform/platform-tests/testSrc/com/intellij/openapi/fileTypes/impl/FileTypesTest.java
@@ -835,6 +835,22 @@ public class FileTypesTest extends HeavyPlatformTestCase {
     assertEquals(1, detectorCalls.get());
   }
 
+  public void testUniqueLanguage() {
+    Map<String, LanguageFileType> map = new HashMap<>();
+    for (FileType type : FileTypeManager.getInstance().getRegisteredFileTypes()) {
+      if (!(type instanceof LanguageFileType)) continue;
+      LanguageFileType languageFileType = (LanguageFileType)type;
+      if (!languageFileType.isSecondary()) {
+        String id = languageFileType.getLanguage().getID();
+        LanguageFileType oldFileType = map.get(id);
+        if (oldFileType != null) {
+          fail("Multiple primary file types for language " + id + ": "+ oldFileType.getName() + ", " + languageFileType.getName());
+        }
+        map.put(id, languageFileType);
+      }
+    }
+  }
+
   @NotNull
   private static FileType createTestFileType() {
     return new FileType() {
diff --git a/plugins/groovy/src/org/jetbrains/plugins/groovy/dgm/DGMFileType.java b/plugins/groovy/src/org/jetbrains/plugins/groovy/dgm/DGMFileType.java
index bc98879b9d85..8d6b8b90b0a2 100644
--- a/plugins/groovy/src/org/jetbrains/plugins/groovy/dgm/DGMFileType.java
+++ b/plugins/groovy/src/org/jetbrains/plugins/groovy/dgm/DGMFileType.java
@@ -15,7 +15,7 @@ import javax.swing.*;
 public class DGMFileType extends LanguageFileType implements FileTypeIdentifiableByVirtualFile {
   public static final DGMFileType INSTANCE = new DGMFileType();
   private DGMFileType() {
-    super(PropertiesLanguage.INSTANCE);
+    super(PropertiesLanguage.INSTANCE, true);
   }
 
   @NotNull