private JComponent createSouthPanel() {
    final JCheckBox checkBox = new JCheckBox(IdeBundle.message("checkbox.narrow.down.on.typing"));
    checkBox.setSelected(PropertiesComponent.getInstance().getBoolean(narrowDownPropertyKey, true));
    checkBox.addChangeListener(
        new ChangeListener() {
          public void stateChanged(ChangeEvent e) {
            myShouldNarrowDown = checkBox.isSelected();
            PropertiesComponent.getInstance()
                .setValue(narrowDownPropertyKey, Boolean.toString(myShouldNarrowDown));

            if (mySpeedSearch.isPopupActive()
                && !StringUtil.isEmpty(mySpeedSearch.getEnteredPrefix())) {
              myAbstractTreeBuilder.queueUpdate();
            }
          }
        });

    checkBox.setFocusable(false);
    UIUtil.applyStyle(UIUtil.ComponentStyle.MINI, checkBox);
    final JPanel panel = new JPanel(new BorderLayout());
    panel.add(checkBox, BorderLayout.WEST);
    return panel;
  }
  private void addCheckbox(final JPanel panel, final TreeAction action) {
    String text =
        action instanceof FileStructureFilter
            ? ((FileStructureFilter) action).getCheckBoxText()
            : action instanceof FileStructureNodeProvider
                ? ((FileStructureNodeProvider) action).getCheckBoxText()
                : null;

    if (text == null) return;

    Shortcut[] shortcuts =
        action instanceof FileStructureFilter
            ? ((FileStructureFilter) action).getShortcut()
            : ((FileStructureNodeProvider) action).getShortcut();

    final JCheckBox chkFilter = new JCheckBox();
    UIUtil.applyStyle(UIUtil.ComponentStyle.SMALL, chkFilter);

    final boolean selected = getDefaultValue(action);
    chkFilter.setSelected(selected);
    myTreeActionsOwner.setActionIncluded(
        action, action instanceof FileStructureFilter ? !selected : selected);
    chkFilter.addActionListener(
        new ActionListener() {
          public void actionPerformed(final ActionEvent e) {
            final boolean state = chkFilter.isSelected();
            if (!myAutoClicked.contains(chkFilter)) {
              saveState(action, state);
            }
            myTreeActionsOwner.setActionIncluded(
                action, action instanceof FileStructureFilter ? !state : state);
            // final String filter = mySpeedSearch.isPopupActive() ?
            // mySpeedSearch.getEnteredPrefix() : null;
            // mySpeedSearch.hidePopup();
            Object selection =
                ContainerUtil.getFirstItem(myAbstractTreeBuilder.getSelectedElements());
            if (selection instanceof FilteringTreeStructure.FilteringNode) {
              selection = ((FilteringTreeStructure.FilteringNode) selection).getDelegate();
            }
            myTreeStructure.rebuildTree();
            myFilteringStructure.rebuild();

            final Object sel = selection;
            final Runnable runnable =
                new Runnable() {
                  public void run() {
                    ApplicationManager.getApplication()
                        .runReadAction(
                            new Runnable() {
                              @Override
                              public void run() {
                                myAbstractTreeBuilder
                                    .refilter(sel, true, false)
                                    .doWhenProcessed(
                                        new Runnable() {
                                          @Override
                                          public void run() {
                                            if (mySpeedSearch.isPopupActive()) {
                                              mySpeedSearch.refreshSelection();
                                            }
                                          }
                                        });
                              }
                            });
                  }
                };
            if (ApplicationManager.getApplication().isUnitTestMode()) {
              runnable.run();
            } else {
              ApplicationManager.getApplication().invokeLater(runnable);
            }
          }
        });
    chkFilter.setFocusable(false);

    if (shortcuts.length > 0) {
      text += " (" + KeymapUtil.getShortcutText(shortcuts[0]) + ")";
      new AnAction() {
        public void actionPerformed(final AnActionEvent e) {
          chkFilter.doClick();
        }
      }.registerCustomShortcutSet(new CustomShortcutSet(shortcuts), myTree);
    }
    chkFilter.setText(text);
    panel.add(chkFilter);
    myCheckBoxes.put(action.getClass(), chkFilter);
  }
  public JComponent createCenterPanel() {
    List<FileStructureFilter> fileStructureFilters = new ArrayList<FileStructureFilter>();
    List<FileStructureNodeProvider> fileStructureNodeProviders =
        new ArrayList<FileStructureNodeProvider>();
    if (myTreeActionsOwner != null) {
      for (Filter filter : myBaseTreeModel.getFilters()) {
        if (filter instanceof FileStructureFilter) {
          final FileStructureFilter fsFilter = (FileStructureFilter) filter;
          myTreeActionsOwner.setActionIncluded(fsFilter, true);
          fileStructureFilters.add(fsFilter);
        }
      }

      if (myBaseTreeModel instanceof ProvidingTreeModel) {
        for (NodeProvider provider : ((ProvidingTreeModel) myBaseTreeModel).getNodeProviders()) {
          if (provider instanceof FileStructureNodeProvider) {
            fileStructureNodeProviders.add((FileStructureNodeProvider) provider);
          }
        }
      }
    }
    final JPanel panel = new JPanel(new BorderLayout());
    JPanel comboPanel = new JPanel(new GridLayout(0, 2, 0, 0));

    final Shortcut[] F4 =
        ActionManager.getInstance()
            .getAction(IdeActions.ACTION_EDIT_SOURCE)
            .getShortcutSet()
            .getShortcuts();
    final Shortcut[] ENTER = CustomShortcutSet.fromString("ENTER").getShortcuts();
    final CustomShortcutSet shortcutSet = new CustomShortcutSet(ArrayUtil.mergeArrays(F4, ENTER));
    new AnAction() {
      public void actionPerformed(AnActionEvent e) {
        final boolean succeeded = navigateSelectedElement();
        if (succeeded) {
          unregisterCustomShortcutSet(panel);
        }
      }
    }.registerCustomShortcutSet(shortcutSet, panel);

    new AnAction() {
      public void actionPerformed(AnActionEvent e) {
        if (mySpeedSearch != null && mySpeedSearch.isPopupActive()) {
          mySpeedSearch.hidePopup();
        } else {
          myPopup.cancel();
        }
      }
    }.registerCustomShortcutSet(CustomShortcutSet.fromString("ESCAPE"), myTree);

    new ClickListener() {
      @Override
      public boolean onClick(MouseEvent e, int clickCount) {
        navigateSelectedElement();
        return true;
      }
    }.installOn(myTree);

    for (FileStructureFilter filter : fileStructureFilters) {
      addCheckbox(comboPanel, filter);
    }

    for (FileStructureNodeProvider provider : fileStructureNodeProviders) {
      addCheckbox(comboPanel, provider);
    }
    myPreferredWidth = Math.max(comboPanel.getPreferredSize().width, 350);
    panel.add(comboPanel, BorderLayout.NORTH);
    JScrollPane scrollPane = ScrollPaneFactory.createScrollPane(myAbstractTreeBuilder.getTree());
    scrollPane.setBorder(IdeBorderFactory.createBorder(SideBorder.TOP | SideBorder.BOTTOM));
    panel.add(scrollPane, BorderLayout.CENTER);
    panel.add(createSouthPanel(), BorderLayout.SOUTH);
    DataManager.registerDataProvider(
        panel,
        new DataProvider() {
          @Override
          public Object getData(@NonNls String dataId) {
            if (PlatformDataKeys.PROJECT.is(dataId)) {
              return myProject;
            }
            if (LangDataKeys.PSI_ELEMENT.is(dataId)) {
              final Object node =
                  ContainerUtil.getFirstItem(myAbstractTreeBuilder.getSelectedElements());
              if (!(node instanceof FilteringTreeStructure.FilteringNode)) return null;
              return getPsi((FilteringTreeStructure.FilteringNode) node);
            }
            if (LangDataKeys.POSITION_ADJUSTER_POPUP.is(dataId)) {
              return myPopup;
            }
            if (PlatformDataKeys.TREE_EXPANDER.is(dataId)) {
              return myTreeExpander;
            }
            return null;
          }
        });

    return panel;
  }