IDEA-34593 Feature lost from 5.0 to 6.0 -> same java class in both view panels via vertical split + CTRL N

platform/platform-impl/src/com/intellij/openapi/fileEditor/impl/FileEditorManagerImpl.java

@@ -552,7 +552,14 @@ public class FileEditorManagerImpl extends FileEditorManagerEx implements Projec
       throw new IllegalArgumentException("file is not valid: " + file);
     }
     assertDispatchThread();
-    return openFileImpl2(getSplitters().getOrCreateCurrentWindow(file), file, focusEditor);
+    EditorsSplitters splitters = getSplitters();
+
+    EditorWindow wndToOpenIn = splitters.getCurrentWindow();
+    if (wndToOpenIn == null) {
+      wndToOpenIn = splitters.getOrCreateCurrentWindow(file);
+    }
+
+    return openFileImpl2(wndToOpenIn, file, focusEditor);
   }
 
   @NotNull public Pair<FileEditor[], FileEditorProvider[]> openFileImpl2(@NotNull final EditorWindow window,