diff --git a/python/src/com/jetbrains/python/documentation/doctest/PyDocstringErrorFilter.java b/python/src/com/jetbrains/python/documentation/doctest/PyDocstringErrorFilter.java
index acf8d24d5f0b..5ee2cade5b98 100644
--- a/python/src/com/jetbrains/python/documentation/doctest/PyDocstringErrorFilter.java
+++ b/python/src/com/jetbrains/python/documentation/doctest/PyDocstringErrorFilter.java
@@ -1,7 +1,6 @@
 package com.jetbrains.python.documentation.doctest;
 
 import com.intellij.codeInsight.highlighting.HighlightErrorFilter;
-import com.intellij.lang.injection.InjectedLanguageManager;
 import com.intellij.psi.PsiErrorElement;
 import com.intellij.psi.PsiFile;
 import org.jetbrains.annotations.NotNull;
@@ -15,6 +14,6 @@ public class PyDocstringErrorFilter extends HighlightErrorFilter {
 
   public boolean shouldHighlightErrorElement(@NotNull final PsiErrorElement element) {
     final PsiFile file = element.getContainingFile();
-    return !(InjectedLanguageManager.getInstance(element.getProject()).isInjectedFragment(file));
+    return !(file instanceof PyDocstringFile);
   }
 }