private void writeComposite(
     final Element res,
     final VirtualFile file,
     final EditorWithProviderComposite composite,
     final boolean pinned,
     final EditorWithProviderComposite selectedEditor) {
   final Element fileElement = new Element("file");
   fileElement.setAttribute("leaf-file-name", file.getName()); // TODO: all files
   final HistoryEntry entry = composite.currentStateAsHistoryEntry();
   entry.writeExternal(fileElement, getManager().getProject());
   fileElement.setAttribute("pinned", Boolean.toString(pinned));
   fileElement.setAttribute(
       "current", Boolean.toString(composite.equals(getManager().getLastSelected())));
   fileElement.setAttribute("current-in-tab", Boolean.toString(composite.equals(selectedEditor)));
   res.addContent(fileElement);
 }
    @Override
    protected JPanel processFiles(@NotNull List<Element> fileElements, final JPanel context) {
      final Ref<EditorWindow> windowRef = new Ref<EditorWindow>();
      UIUtil.invokeAndWaitIfNeeded(
          new Runnable() {
            @Override
            public void run() {
              windowRef.set(context == null ? createEditorWindow() : findWindowWith(context));
            }
          });
      final EditorWindow window = windowRef.get();
      LOG.assertTrue(window != null);
      VirtualFile focusedFile = null;

      for (int i = 0; i < fileElements.size(); i++) {
        final Element file = fileElements.get(i);
        if (i == 0) {
          EditorTabbedContainer tabbedPane = window.getTabbedPane();
          if (tabbedPane != null) {
            try {
              int limit =
                  Integer.parseInt(
                      file.getParentElement()
                          .getAttributeValue(
                              JBTabsImpl.SIDE_TABS_SIZE_LIMIT_KEY.toString(),
                              String.valueOf(JBTabsImpl.DEFAULT_MAX_TAB_WIDTH)));
              UIUtil.putClientProperty(
                  tabbedPane.getComponent(), JBTabsImpl.SIDE_TABS_SIZE_LIMIT_KEY, limit);
            } catch (NumberFormatException e) {
              // ignore
            }
          }
        }
        try {
          final FileEditorManagerImpl fileEditorManager = getManager();
          Element historyElement = file.getChild(HistoryEntry.TAG);
          final HistoryEntry entry =
              HistoryEntry.createLight(fileEditorManager.getProject(), historyElement);
          final VirtualFile virtualFile = entry.getFile();
          if (virtualFile == null)
            throw new InvalidDataException("No file exists: " + entry.getFilePointer().getUrl());
          Document document =
              ApplicationManager.getApplication()
                  .runReadAction(
                      new Computable<Document>() {
                        @Override
                        public Document compute() {
                          return virtualFile.isValid()
                              ? FileDocumentManager.getInstance().getDocument(virtualFile)
                              : null;
                        }
                      });
          final boolean isCurrentInTab =
              Boolean.valueOf(file.getAttributeValue(CURRENT_IN_TAB)).booleanValue();
          Boolean pin = Boolean.valueOf(file.getAttributeValue(PINNED));
          fileEditorManager.openFileImpl4(
              window, virtualFile, entry, isCurrentInTab, isCurrentInTab, pin, i);
          if (isCurrentInTab) {
            focusedFile = virtualFile;
          }
          if (document != null) {
            // This is just to make sure document reference is kept on stack till this point
            // so that document is available for folding state deserialization in HistoryEntry
            // constructor
            // and that document will be created only once during file opening
            document.putUserData(DUMMY_KEY, null);
          }
          updateProgress();
        } catch (InvalidDataException e) {
          if (ApplicationManager.getApplication().isUnitTestMode()) {
            LOG.error(e);
          }
        }
      }
      if (focusedFile != null) {
        getManager().addSelectionRecord(focusedFile, window);
      }
      return window.myPanel;
    }