diff --git a/platform/lang-impl/src/com/intellij/openapi/file/exclude/EnforcedPlainTextFileTypeManager.java b/platform/lang-impl/src/com/intellij/openapi/file/exclude/EnforcedPlainTextFileTypeManager.java
index ee685f7257a1..a77bb23e90e9 100644
--- a/platform/lang-impl/src/com/intellij/openapi/file/exclude/EnforcedPlainTextFileTypeManager.java
+++ b/platform/lang-impl/src/com/intellij/openapi/file/exclude/EnforcedPlainTextFileTypeManager.java
@@ -25,6 +25,7 @@ import com.intellij.openapi.fileTypes.StdFileTypes;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.project.ProjectManager;
 import com.intellij.openapi.project.ProjectManagerListener;
+import com.intellij.openapi.roots.ProjectFileIndex;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.openapi.vfs.VirtualFileWithId;
 import com.intellij.util.FileContentUtilCore;
@@ -93,8 +94,9 @@ public class EnforcedPlainTextFileTypeManager implements ProjectManagerListener
   private void setPlainTextStatus(@NotNull final Project project, final boolean isAdded, @NotNull final VirtualFile... files) {
     ApplicationManager.getApplication().runWriteAction(() -> {
       ProjectPlainTextFileTypeManager projectManager = ProjectPlainTextFileTypeManager.getInstance(project);
+      ProjectFileIndex fileIndex = ProjectFileIndex.getInstance(project);
       for (VirtualFile file : files) {
-        if (projectManager.isInContent(file) || projectManager.isInLibrarySource(file)) {
+        if (fileIndex.isInContent(file) || fileIndex.isInLibrarySource(file) || fileIndex.isExcluded(file)) {
           ensureProjectFileSetAdded(project, projectManager);
           if (isAdded ?
               projectManager.addFile(file) :
diff --git a/platform/lang-impl/src/com/intellij/openapi/file/exclude/ProjectPlainTextFileTypeManager.java b/platform/lang-impl/src/com/intellij/openapi/file/exclude/ProjectPlainTextFileTypeManager.java
index 0432f38e7f37..e72013387982 100644
--- a/platform/lang-impl/src/com/intellij/openapi/file/exclude/ProjectPlainTextFileTypeManager.java
+++ b/platform/lang-impl/src/com/intellij/openapi/file/exclude/ProjectPlainTextFileTypeManager.java
@@ -18,29 +18,12 @@ package com.intellij.openapi.file.exclude;
 import com.intellij.openapi.components.ServiceManager;
 import com.intellij.openapi.components.State;
 import com.intellij.openapi.project.Project;
-import com.intellij.openapi.roots.ProjectFileIndex;
-import com.intellij.openapi.vfs.VirtualFile;
-import org.jetbrains.annotations.NotNull;
 
 /**
  * @author Rustam Vishnyakov
  */
 @State(name = "ProjectPlainTextFileTypeManager")
 public class ProjectPlainTextFileTypeManager extends PersistentFileSetManager {
-  private final ProjectFileIndex myIndex;
-
-  public ProjectPlainTextFileTypeManager(ProjectFileIndex projectFileIndex) {
-    myIndex = projectFileIndex;
-  }
-
-  boolean isInContent(@NotNull VirtualFile file) {
-    return myIndex.isInContent(file);
-  }
-
-  boolean isInLibrarySource(@NotNull final VirtualFile file) {
-    return myIndex.isInLibrarySource(file);
-  }
-
   public static ProjectPlainTextFileTypeManager getInstance(Project project) {
     return ServiceManager.getService(project, ProjectPlainTextFileTypeManager.class);
   }