diff --git a/json/src/com/jetbrains/jsonSchema/JsonSchemaFileTypeManager.java b/json/src/com/jetbrains/jsonSchema/JsonSchemaFileTypeManager.java
index f7656c77ee3c..6674ad0887d7 100644
--- a/json/src/com/jetbrains/jsonSchema/JsonSchemaFileTypeManager.java
+++ b/json/src/com/jetbrains/jsonSchema/JsonSchemaFileTypeManager.java
@@ -30,7 +30,7 @@ import java.util.Collection;
  * @author Irina.Chernushina on 5/30/2016.
  */
 public class JsonSchemaFileTypeManager implements ProjectManagerListener {
-  private final Collection<VirtualFile> myFileSets = ContainerUtil.createConcurrentList();
+  private final Collection<VirtualFile> myFileSets = ContainerUtil.newConcurrentSet();
   private volatile boolean mySetsInitialized;
   private static final Object LOCK = new Object();