diff --git a/platform/platform-impl/src/com/intellij/ide/impl/ProjectUtil.java b/platform/platform-impl/src/com/intellij/ide/impl/ProjectUtil.java
index 4f42abb3004b..5a5e2a16c7b0 100644
--- a/platform/platform-impl/src/com/intellij/ide/impl/ProjectUtil.java
+++ b/platform/platform-impl/src/com/intellij/ide/impl/ProjectUtil.java
@@ -283,26 +283,26 @@ public class ProjectUtil {
 
   public static boolean isSameProject(String projectFilePath, @NotNull Project project) {
     IProjectStore projectStore = ProjectKt.getStateStore(project);
-
-    String toOpen = FileUtil.toSystemIndependentName(projectFilePath);
-    String existing = projectStore.getProjectFilePath();
-
-    String existingBaseDir = projectStore.getProjectBasePath();
-    if (existingBaseDir == null) {
+    String existingBaseDirPath = projectStore.getProjectBasePath();
+    if (existingBaseDirPath == null) {
       // could be null if not yet initialized
       return false;
     }
 
-    final File openFile = new File(toOpen);
-    if (openFile.isDirectory()) {
-      return FileUtil.pathsEqual(toOpen, existingBaseDir);
-    }
-    if (StorageScheme.DIRECTORY_BASED == projectStore.getStorageScheme()) {
-      // todo: check if IPR is located not under the project base dir
-      return FileUtil.pathsEqual(FileUtil.toSystemIndependentName(openFile.getParentFile().getPath()), existingBaseDir);
+    final File projectFile = new File(projectFilePath);
+    if (projectFile.isDirectory()) {
+      return FileUtil.pathsEqual(projectFilePath, existingBaseDirPath);
     }
 
-    return FileUtil.pathsEqual(toOpen, existing);
+    if (projectStore.getStorageScheme() == StorageScheme.DEFAULT) {
+      return FileUtil.pathsEqual(projectFilePath, projectStore.getProjectFilePath());
+    }
+
+    File parent = projectFile.getParentFile();
+    if (parent.getName().equals(Project.DIRECTORY_STORE_FOLDER)) {
+      parent = parent.getParentFile();
+    }
+    return parent != null && FileUtil.pathsEqual(parent.getPath(), existingBaseDirPath);
   }
 
   public static void focusProjectWindow(final Project p, boolean executeIfAppInactive) {
diff --git a/platform/platform-tests/testSrc/com/intellij/openapi/project/impl/ProjectOpeningTest.java b/platform/platform-tests/testSrc/com/intellij/openapi/project/impl/ProjectOpeningTest.java
index d6a016f6f346..be90a7042fba 100644
--- a/platform/platform-tests/testSrc/com/intellij/openapi/project/impl/ProjectOpeningTest.java
+++ b/platform/platform-tests/testSrc/com/intellij/openapi/project/impl/ProjectOpeningTest.java
@@ -15,6 +15,7 @@
  */
 package com.intellij.openapi.project.impl;
 
+import com.intellij.ide.impl.ProjectUtil;
 import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.progress.ProgressIndicator;
 import com.intellij.openapi.progress.ProgressManager;
@@ -29,6 +30,7 @@ import com.intellij.testFramework.PlatformTestUtil;
 import org.jetbrains.annotations.NotNull;
 
 import java.io.File;
+import java.io.IOException;
 
 import static com.intellij.openapi.startup.StartupActivity.POST_STARTUP_ACTIVITY;
 
@@ -85,6 +87,31 @@ public class ProjectOpeningTest extends PlatformTestCase {
 
   */
 
+  public void testIsSameProjectForDirectoryBasedProject() throws IOException {
+    File projectDir = createTempDir("project");
+    Project dirBasedProject = ProjectManager.getInstance().createProject("project", projectDir.getAbsolutePath());
+    disposeOnTearDown(dirBasedProject);
+
+    assertTrue(ProjectUtil.isSameProject(projectDir.getAbsolutePath(), dirBasedProject));
+    assertFalse(ProjectUtil.isSameProject(createTempDir("project2").getAbsolutePath(), dirBasedProject));
+    File iprFilePath = new File(projectDir, "project.ipr");
+    assertTrue(ProjectUtil.isSameProject(iprFilePath.getAbsolutePath(), dirBasedProject));
+    File miscXmlFilePath = new File(projectDir, ".idea/misc.xml");
+    assertTrue(ProjectUtil.isSameProject(miscXmlFilePath.getAbsolutePath(), dirBasedProject));
+  }
+
+  public void testIsSameProjectForFileBasedProject() throws IOException {
+    File projectDir = createTempDir("project");
+    File iprFilePath = new File(projectDir, "project.ipr");
+    Project fileBasedProject = ProjectManager.getInstance().createProject(iprFilePath.getName(), iprFilePath.getAbsolutePath());
+    disposeOnTearDown(fileBasedProject);
+
+    assertTrue(ProjectUtil.isSameProject(projectDir.getAbsolutePath(), fileBasedProject));
+    assertFalse(ProjectUtil.isSameProject(createTempDir("project2").getAbsolutePath(), fileBasedProject));
+    File iprFilePath2 = new File(projectDir, "project2.ipr");
+    assertFalse(ProjectUtil.isSameProject(iprFilePath2.getAbsolutePath(), fileBasedProject));
+  }
+
   private static void closeProject(final Project project) {
     if (project != null && !project.isDisposed()) {
       ProjectManager.getInstance().closeProject(project);