diff --git a/platform/core-api/src/com/intellij/openapi/project/Project.java b/platform/core-api/src/com/intellij/openapi/project/Project.java
index a3ff009226a6..4ba32c2e0940 100644
--- a/platform/core-api/src/com/intellij/openapi/project/Project.java
+++ b/platform/core-api/src/com/intellij/openapi/project/Project.java
@@ -32,7 +32,7 @@ import org.jetbrains.annotations.Nullable;
  * <p>To get the list of all open projects, use {@code ProjectManager.getInstance().getOpenProjects()}.
  */
 public interface Project extends ComponentManager, AreaInstance {
-  String DIRECTORY_STORE_FOLDER = ProjectCoreUtil.DIRECTORY_BASED_PROJECT_DIR;
+  String DIRECTORY_STORE_FOLDER = ".idea";
 
   /**
    * Returns a name ot the project. For a directory-based project it's an arbitrary string specified by user at project creation
diff --git a/platform/core-api/src/com/intellij/openapi/project/ProjectCoreUtil.java b/platform/core-api/src/com/intellij/openapi/project/ProjectCoreUtil.java
index 01de8b1b9e0b..b03915ad301a 100644
--- a/platform/core-api/src/com/intellij/openapi/project/ProjectCoreUtil.java
+++ b/platform/core-api/src/com/intellij/openapi/project/ProjectCoreUtil.java
@@ -24,20 +24,22 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 /**
- * Author: dmitrylomov
+ * @author dmitrylomov
  */
 public class ProjectCoreUtil {
-  public static final String DIRECTORY_BASED_PROJECT_DIR = ".idea";
+  /** @deprecated use {@link Project#DIRECTORY_STORE_FOLDER} (to be removed in IDEA 17) */
+  @SuppressWarnings("unused")
+  public static final String DIRECTORY_BASED_PROJECT_DIR = Project.DIRECTORY_STORE_FOLDER;
 
   public static boolean isProjectOrWorkspaceFile(@NotNull VirtualFile file) {
     return isProjectOrWorkspaceFile(file, file.getFileType());
   }
 
-  public static boolean isProjectOrWorkspaceFile(@NotNull VirtualFile file, @Nullable final FileType fileType) {
+  public static boolean isProjectOrWorkspaceFile(@NotNull VirtualFile file, @Nullable FileType fileType) {
     if (fileType instanceof InternalFileType) return true;
     VirtualFile parent = file.isDirectory() ? file: file.getParent();
     while (parent != null) {
-      if (Comparing.equal(parent.getNameSequence(), DIRECTORY_BASED_PROJECT_DIR, SystemInfoRt.isFileSystemCaseSensitive)) return true;
+      if (Comparing.equal(parent.getNameSequence(), Project.DIRECTORY_STORE_FOLDER, SystemInfoRt.isFileSystemCaseSensitive)) return true;
       parent = parent.getParent();
     }
     return false;
@@ -51,4 +53,4 @@ public class ProjectCoreUtil {
     return theProject;
   }
   public static volatile Project theProject;
-}
+}
\ No newline at end of file