diff --git a/platform/core-api/src/com/intellij/psi/search/GlobalSearchScope.java b/platform/core-api/src/com/intellij/psi/search/GlobalSearchScope.java
index fbb148a74de0..0b74f65ae63f 100644
--- a/platform/core-api/src/com/intellij/psi/search/GlobalSearchScope.java
+++ b/platform/core-api/src/com/intellij/psi/search/GlobalSearchScope.java
@@ -30,10 +30,7 @@ import org.jetbrains.annotations.NonNls;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.List;
+import java.util.*;
 
 public abstract class GlobalSearchScope extends SearchScope implements ProjectAwareFileFilter {
   private static final Logger LOG = Logger.getInstance("#com.intellij.psi.search.GlobalSearchScope");
@@ -586,8 +583,8 @@ public abstract class GlobalSearchScope extends SearchScope implements ProjectAw
 
   public static final GlobalSearchScope EMPTY_SCOPE = new EmptyScope();
 
-  private static class FileScope extends GlobalSearchScope {
-    private final VirtualFile myVirtualFile;
+  private static class FileScope extends GlobalSearchScope implements Iterable<VirtualFile> {
+    private final VirtualFile myVirtualFile; // files can be out of project roots
     private final Module myModule;
 
     private FileScope(@NotNull Project project, VirtualFile virtualFile) {
@@ -620,10 +617,15 @@ public abstract class GlobalSearchScope extends SearchScope implements ProjectAw
     public String toString() {
       return "File :"+myVirtualFile;
     }
+
+    @Override
+    public Iterator<VirtualFile> iterator() {
+      return Collections.singletonList(myVirtualFile).iterator();
+    }
   }
 
-  public static class FilesScope extends GlobalSearchScope {
-    private final Collection<VirtualFile> myFiles;
+  public static class FilesScope extends GlobalSearchScope implements Iterable<VirtualFile> {
+    private final Collection<VirtualFile> myFiles; // files can be out of project roots
 
     public FilesScope(final Project project, @NotNull Collection<VirtualFile> files) {
       super(project);
@@ -666,5 +668,10 @@ public abstract class GlobalSearchScope extends SearchScope implements ProjectAw
       List<VirtualFile> files = myFiles.size() <= 20 ? new ArrayList<VirtualFile>(myFiles) : new ArrayList<VirtualFile>(myFiles).subList(0,20);
       return "Files: ("+ files +")";
     }
+
+    @Override
+    public Iterator<VirtualFile> iterator() {
+      return myFiles.iterator();
+    }
   }
 }
diff --git a/platform/lang-api/src/com/intellij/psi/search/GlobalSearchScopes.java b/platform/lang-api/src/com/intellij/psi/search/GlobalSearchScopes.java
index bbeb3e888492..3acfe338d499 100644
--- a/platform/lang-api/src/com/intellij/psi/search/GlobalSearchScopes.java
+++ b/platform/lang-api/src/com/intellij/psi/search/GlobalSearchScopes.java
@@ -18,13 +18,9 @@ package com.intellij.psi.search;
 import com.intellij.openapi.fileEditor.FileEditorManager;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.vfs.VirtualFile;
-import com.intellij.psi.PsiElement;
-import com.intellij.psi.PsiFile;
-import com.intellij.psi.PsiManager;
 import org.jetbrains.annotations.NotNull;
 
-import java.util.ArrayList;
-import java.util.List;
+import java.util.Arrays;
 
 /**
  * @author yole
@@ -34,16 +30,8 @@ public class GlobalSearchScopes extends GlobalSearchScopesCore {
   }
 
   @NotNull
-  public static SearchScope openFilesScope(@NotNull Project project) {
+  public static GlobalSearchScope openFilesScope(@NotNull Project project) {
     final VirtualFile[] files = FileEditorManager.getInstance(project).getOpenFiles();
-    // We can not use GlobalSearchScope as it is usually bound to project and used via filtering of project / library roots
-    // Open files can be out of project roots e.g. arbitrary open file so we go LocalSearchScope way, filling it with elements to process
-    List<PsiElement> psiFiles = new ArrayList<PsiElement>(files.length);
-    PsiManager psiManager = PsiManager.getInstance(project);
-    for(VirtualFile file:files) {
-      PsiFile psiFile = psiManager.findFile(file);
-      if (psiFile != null) psiFiles.add(psiFile);
-    }
-    return new LocalSearchScope(psiFiles.toArray(new PsiElement[psiFiles.size()]), "Open Files");
+    return GlobalSearchScope.filesScope(project, Arrays.asList(files), "Open Files");
   }
 }
diff --git a/platform/lang-impl/src/com/intellij/find/impl/FindInProjectTask.java b/platform/lang-impl/src/com/intellij/find/impl/FindInProjectTask.java
index aa344c44be47..59adf1e62bd0 100644
--- a/platform/lang-impl/src/com/intellij/find/impl/FindInProjectTask.java
+++ b/platform/lang-impl/src/com/intellij/find/impl/FindInProjectTask.java
@@ -290,6 +290,10 @@ class FindInProjectTask {
       for (VirtualFile file : getLocalScopeFiles((LocalSearchScope)customScope)) {
         iterator.processFile(file);
       }
+    } else if (customScope instanceof Iterable) {  // GlobalSearchScope can span files out of project roots e.g. FileScope / FilesScope
+      for (VirtualFile file : (Iterable<VirtualFile>)customScope) {
+        iterator.processFile(file);
+      }
     }
     else if (myPsiDirectory != null) {
       ApplicationManager.getApplication().runReadAction(new Runnable() {