private boolean validateStartMenuGroup() {
    NSISWizardSettings settings = mWizard.getSettings();

    if (settings.isCreateStartMenuGroup()) {
      String startMenuGroup = settings.getStartMenuGroup();
      String[] parts = Common.tokenize(startMenuGroup, File.separatorChar);
      if (Common.isEmptyArray(parts)) {
        setErrorMessage(
            EclipseNSISPlugin.getFormattedString(
                "invalid.start.menu.group.error", new String[] {startMenuGroup})); // $NON-NLS-1$
        return false;
      }
      for (int i = 0; i < parts.length; i++) {
        if (!IOUtility.isValidFileName(parts[i])) {
          setErrorMessage(
              EclipseNSISPlugin.getFormattedString(
                  "invalid.start.menu.group.error", new String[] {startMenuGroup})); // $NON-NLS-1$
          return false;
        }
      }
    }
    return true;
  }
  private void createLanguagesGroup(Composite parent) {
    final Group langGroup =
        NSISWizardDialogUtil.createGroup(
            parent, 1, "language.support.group.label", null, false); // $NON-NLS-1$
    GridData data = (GridData) langGroup.getLayoutData();
    data.verticalAlignment = SWT.FILL;
    data.grabExcessVerticalSpace = true;
    data.horizontalAlignment = SWT.FILL;
    data.grabExcessHorizontalSpace = true;

    NSISWizardSettings settings = mWizard.getSettings();

    final Button enableLangSupport =
        NSISWizardDialogUtil.createCheckBox(
            langGroup,
            "enable.language.support.label",
            settings.isEnableLanguageSupport(),
            true,
            null,
            false); //$NON-NLS-1$
    enableLangSupport.addSelectionListener(
        new SelectionAdapter() {
          @Override
          public void widgetSelected(SelectionEvent e) {
            boolean selection = enableLangSupport.getSelection();
            mWizard.getSettings().setEnableLanguageSupport(selection);
            validateField(LANG_CHECK);
          }
        });

    final MasterSlaveController m = new MasterSlaveController(enableLangSupport);

    final Composite listsComposite = new Composite(langGroup, SWT.NONE);
    data = new GridData(SWT.FILL, SWT.FILL, true, true);
    listsComposite.setLayoutData(data);

    GridLayout layout = new GridLayout(2, true);
    layout.marginHeight = 0;
    layout.marginWidth = 0;
    listsComposite.setLayout(layout);

    java.util.List<NSISLanguage> selectedLanguages = settings.getLanguages();
    if (selectedLanguages.isEmpty()) {
      NSISLanguage defaultLanguage = NSISLanguageManager.getInstance().getDefaultLanguage();
      if (defaultLanguage != null) {
        selectedLanguages.add(defaultLanguage);
      }
    }
    java.util.List<NSISLanguage> availableLanguages =
        NSISLanguageManager.getInstance().getLanguages();
    availableLanguages.removeAll(selectedLanguages);

    Composite leftComposite = new Composite(listsComposite, SWT.NONE);
    leftComposite.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
    layout = new GridLayout(2, false);
    layout.marginHeight = 0;
    layout.marginWidth = 0;
    leftComposite.setLayout(layout);

    ((GridData)
                NSISWizardDialogUtil.createLabel(
                        leftComposite,
                        "available.languages.label", //$NON-NLS-1$
                        true,
                        m,
                        false)
                    .getLayoutData())
            .horizontalSpan =
        2;

    final List availableLangList =
        new List(leftComposite, SWT.BORDER | SWT.H_SCROLL | SWT.V_SCROLL | SWT.MULTI);
    data = new GridData(SWT.FILL, SWT.FILL, true, true);
    Dialog.applyDialogFont(availableLangList);
    data.heightHint = Common.calculateControlSize(availableLangList, 0, 12).y;
    availableLangList.setLayoutData(data);
    m.addSlave(availableLangList);

    final ListViewer availableLangViewer = new ListViewer(availableLangList);
    CollectionContentProvider collectionContentProvider = new CollectionContentProvider();
    availableLangViewer.setContentProvider(collectionContentProvider);
    availableLangViewer.setInput(availableLanguages);
    availableLangViewer.setSorter(new ViewerSorter(cLanguageCollator));

    final Composite buttonsComposite1 = new Composite(leftComposite, SWT.NONE);
    layout = new GridLayout(1, false);
    layout.marginHeight = 0;
    layout.marginWidth = 0;
    buttonsComposite1.setLayout(layout);
    data = new GridData(SWT.FILL, SWT.CENTER, false, false);
    buttonsComposite1.setLayoutData(data);

    final Button allRightButton = new Button(buttonsComposite1, SWT.PUSH);
    data = new GridData(SWT.FILL, SWT.CENTER, true, false);
    allRightButton.setLayoutData(data);
    allRightButton.setImage(
        EclipseNSISPlugin.getImageManager()
            .getImage(EclipseNSISPlugin.getResourceString("all.right.icon"))); // $NON-NLS-1$
    allRightButton.setToolTipText(
        EclipseNSISPlugin.getResourceString("all.right.tooltip")); // $NON-NLS-1$

    final Button rightButton = new Button(buttonsComposite1, SWT.PUSH);
    data = new GridData(SWT.FILL, SWT.CENTER, true, false);
    rightButton.setLayoutData(data);
    rightButton.setImage(
        EclipseNSISPlugin.getImageManager()
            .getImage(EclipseNSISPlugin.getResourceString("right.icon"))); // $NON-NLS-1$
    rightButton.setToolTipText(EclipseNSISPlugin.getResourceString("right.tooltip")); // $NON-NLS-1$

    final Button leftButton = new Button(buttonsComposite1, SWT.PUSH);
    data = new GridData(SWT.FILL, SWT.CENTER, true, false);
    leftButton.setLayoutData(data);
    leftButton.setImage(
        EclipseNSISPlugin.getImageManager()
            .getImage(EclipseNSISPlugin.getResourceString("left.icon"))); // $NON-NLS-1$
    leftButton.setToolTipText(EclipseNSISPlugin.getResourceString("left.tooltip")); // $NON-NLS-1$

    final Button allLeftButton = new Button(buttonsComposite1, SWT.PUSH);
    data = new GridData(SWT.FILL, SWT.CENTER, true, false);
    allLeftButton.setLayoutData(data);
    allLeftButton.setImage(
        EclipseNSISPlugin.getImageManager()
            .getImage(EclipseNSISPlugin.getResourceString("all.left.icon"))); // $NON-NLS-1$
    allLeftButton.setToolTipText(
        EclipseNSISPlugin.getResourceString("all.left.tooltip")); // $NON-NLS-1$

    Composite rightComposite = new Composite(listsComposite, SWT.NONE);
    rightComposite.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
    layout = new GridLayout(2, false);
    layout.marginHeight = 0;
    layout.marginWidth = 0;
    rightComposite.setLayout(layout);

    ((GridData)
                NSISWizardDialogUtil.createLabel(
                        rightComposite,
                        "selected.languages.label", //$NON-NLS-1$
                        true,
                        m,
                        isScriptWizard())
                    .getLayoutData())
            .horizontalSpan =
        2;

    final List selectedLangList =
        new List(rightComposite, SWT.BORDER | SWT.H_SCROLL | SWT.V_SCROLL | SWT.MULTI);
    data = new GridData(SWT.FILL, SWT.FILL, true, true);
    Dialog.applyDialogFont(selectedLangList);
    data.heightHint = Common.calculateControlSize(selectedLangList, 0, 12).y;
    selectedLangList.setLayoutData(data);
    m.addSlave(selectedLangList);

    final ListViewer selectedLangViewer = new ListViewer(selectedLangList);
    selectedLangViewer.setContentProvider(collectionContentProvider);
    selectedLangViewer.setInput(selectedLanguages);

    final ListViewerUpDownMover<java.util.List<NSISLanguage>, NSISLanguage> mover =
        new ListViewerUpDownMover<java.util.List<NSISLanguage>, NSISLanguage>() {
          @Override
          @SuppressWarnings("unchecked")
          protected java.util.List<NSISLanguage> getAllElements() {
            return (java.util.List<NSISLanguage>) ((ListViewer) getViewer()).getInput();
          }

          @Override
          protected void updateStructuredViewerInput(
              java.util.List<NSISLanguage> input,
              java.util.List<NSISLanguage> elements,
              java.util.List<NSISLanguage> move,
              boolean isDown) {
            (input).clear();
            (input).addAll(elements);
          }
        };

    mover.setViewer(selectedLangViewer);

    final Composite buttonsComposite2 = new Composite(rightComposite, SWT.NONE);
    layout = new GridLayout(1, false);
    layout.marginHeight = 0;
    layout.marginWidth = 0;
    buttonsComposite2.setLayout(layout);
    data = new GridData(SWT.FILL, SWT.CENTER, false, false);
    buttonsComposite2.setLayoutData(data);

    final Button upButton = new Button(buttonsComposite2, SWT.PUSH);
    data = new GridData(SWT.FILL, SWT.CENTER, true, false);
    upButton.setLayoutData(data);
    upButton.setImage(
        EclipseNSISPlugin.getImageManager()
            .getImage(EclipseNSISPlugin.getResourceString("up.icon"))); // $NON-NLS-1$
    upButton.setToolTipText(EclipseNSISPlugin.getResourceString("up.tooltip")); // $NON-NLS-1$
    m.addSlave(upButton);

    final Button downButton = new Button(buttonsComposite2, SWT.PUSH);
    data = new GridData(SWT.FILL, SWT.CENTER, true, false);
    downButton.setLayoutData(data);
    downButton.setImage(
        EclipseNSISPlugin.getImageManager()
            .getImage(EclipseNSISPlugin.getResourceString("down.icon"))); // $NON-NLS-1$
    downButton.setToolTipText(EclipseNSISPlugin.getResourceString("down.tooltip")); // $NON-NLS-1$
    m.addSlave(downButton);

    Composite langOptions = langGroup;
    boolean showSupportedLangOption =
        NSISPreferences.getInstance().getNSISVersion().compareTo(INSISVersions.VERSION_2_26) >= 0;
    if (showSupportedLangOption) {
      langOptions = new Composite(langGroup, SWT.None);
      layout = new GridLayout(2, false);
      layout.marginHeight = 0;
      layout.marginWidth = 0;
      langOptions.setLayout(layout);
      data = new GridData(SWT.FILL, SWT.FILL, true, false);
      langOptions.setLayoutData(data);
    }

    final Button selectLang =
        NSISWizardDialogUtil.createCheckBox(
            langOptions,
            "select.language.label",
            settings.isSelectLanguage(),
            true,
            m,
            false); //$NON-NLS-1$

    final Button displaySupported;
    if (showSupportedLangOption) {
      ((GridData) selectLang.getLayoutData()).horizontalSpan = 1;
      displaySupported =
          NSISWizardDialogUtil.createCheckBox(
              langOptions,
              "display.supported.languages.label",
              settings.isDisplaySupportedLanguages(), // $NON-NLS-1$
              true,
              m,
              false);
      ((GridData) displaySupported.getLayoutData()).horizontalSpan = 1;
      displaySupported.addSelectionListener(
          new SelectionAdapter() {
            @Override
            public void widgetSelected(SelectionEvent e) {
              mWizard.getSettings().setDisplaySupportedLanguages(displaySupported.getSelection());
            }
          });
    } else {
      displaySupported = null;
    }

    final MasterSlaveEnabler mse =
        new MasterSlaveEnabler() {
          public void enabled(Control control, boolean flag) {}

          @SuppressWarnings("unchecked")
          public boolean canEnable(Control control) {
            NSISWizardSettings settings = mWizard.getSettings();

            if (control == allRightButton) {
              return settings.isEnableLanguageSupport()
                  && availableLangViewer.getList().getItemCount() > 0;
            } else if (control == rightButton) {
              return settings.isEnableLanguageSupport()
                  && !availableLangViewer.getSelection().isEmpty();
            } else if (control == allLeftButton) {
              return settings.isEnableLanguageSupport()
                  && selectedLangViewer.getList().getItemCount() > 0;
            } else if (control == leftButton) {
              return settings.isEnableLanguageSupport()
                  && !selectedLangViewer.getSelection().isEmpty();
            } else if (control == upButton) {
              return settings.isEnableLanguageSupport() && mover.canMoveUp();
            } else if (control == downButton) {
              return settings.isEnableLanguageSupport() && mover.canMoveDown();
            } else if (control == selectLang) {
              java.util.List<NSISLanguage> selectedLanguages =
                  (java.util.List<NSISLanguage>) selectedLangViewer.getInput();
              return settings.getInstallerType() != INSTALLER_TYPE_SILENT
                  && settings.isEnableLanguageSupport()
                  && selectedLanguages.size() > 1;
            } else if (control == displaySupported && displaySupported != null) {
              java.util.List<NSISLanguage> selectedLanguages =
                  (java.util.List<NSISLanguage>) selectedLangViewer.getInput();
              return settings.getInstallerType() != INSTALLER_TYPE_SILENT
                  && settings.isEnableLanguageSupport()
                  && selectedLanguages.size() > 1
                  && selectLang.getSelection();
            } else {
              return true;
            }
          }
        };
    m.addSlave(rightButton, mse);
    m.addSlave(allRightButton, mse);
    m.addSlave(leftButton, mse);
    m.addSlave(allLeftButton, mse);
    m.setEnabler(upButton, mse);
    m.setEnabler(downButton, mse);
    m.setEnabler(selectLang, mse);
    if (displaySupported != null) {
      m.setEnabler(displaySupported, mse);
    }

    selectLang.addSelectionListener(
        new SelectionAdapter() {
          @Override
          public void widgetSelected(SelectionEvent e) {
            mWizard.getSettings().setSelectLanguage(selectLang.getSelection());
            if (displaySupported != null) {
              displaySupported.setEnabled(mse.canEnable(displaySupported));
            }
          }
        });

    final Runnable langRunnable =
        new Runnable() {
          public void run() {
            availableLangViewer.refresh(false);
            selectedLangViewer.refresh(false);
            allRightButton.setEnabled(mse.canEnable(allRightButton));
            allLeftButton.setEnabled(mse.canEnable(allLeftButton));
            rightButton.setEnabled(mse.canEnable(rightButton));
            leftButton.setEnabled(mse.canEnable(leftButton));
            upButton.setEnabled(mse.canEnable(upButton));
            downButton.setEnabled(mse.canEnable(downButton));
            selectLang.setEnabled(mse.canEnable(selectLang));
            if (displaySupported != null) {
              displaySupported.setEnabled(mse.canEnable(displaySupported));
            }
            setPageComplete(validateField(LANG_CHECK));
          }
        };

    rightButton.addSelectionListener(
        new SelectionAdapter() {
          @Override
          public void widgetSelected(SelectionEvent se) {
            moveAcross(
                availableLangViewer,
                selectedLangViewer,
                Common.makeGenericList(
                    NSISLanguage.class,
                    ((IStructuredSelection) availableLangViewer.getSelection()).toList()));
            langRunnable.run();
          }
        });
    allRightButton.addSelectionListener(
        new SelectionAdapter() {
          @Override
          @SuppressWarnings("unchecked")
          public void widgetSelected(SelectionEvent se) {
            moveAcross(
                availableLangViewer,
                selectedLangViewer,
                (java.util.List<NSISLanguage>) availableLangViewer.getInput());
            langRunnable.run();
          }
        });
    leftButton.addSelectionListener(
        new SelectionAdapter() {
          @Override
          public void widgetSelected(SelectionEvent se) {
            moveAcross(
                selectedLangViewer,
                availableLangViewer,
                Common.makeGenericList(
                    NSISLanguage.class,
                    ((IStructuredSelection) selectedLangViewer.getSelection()).toList()));
            langRunnable.run();
          }
        });
    allLeftButton.addSelectionListener(
        new SelectionAdapter() {
          @Override
          @SuppressWarnings("unchecked")
          public void widgetSelected(SelectionEvent se) {
            moveAcross(
                selectedLangViewer,
                availableLangViewer,
                (java.util.List<NSISLanguage>) selectedLangViewer.getInput());
            langRunnable.run();
          }
        });
    upButton.addSelectionListener(
        new SelectionAdapter() {
          @Override
          public void widgetSelected(SelectionEvent se) {
            mover.moveUp();
            langRunnable.run();
          }
        });
    downButton.addSelectionListener(
        new SelectionAdapter() {
          @Override
          public void widgetSelected(SelectionEvent se) {
            mover.moveDown();
            langRunnable.run();
          }
        });

    availableLangViewer.addSelectionChangedListener(
        new ISelectionChangedListener() {
          public void selectionChanged(SelectionChangedEvent event) {
            rightButton.setEnabled(mse.canEnable(rightButton));
            allRightButton.setEnabled(mse.canEnable(allRightButton));
          }
        });
    availableLangViewer
        .getList()
        .addSelectionListener(
            new SelectionAdapter() {
              @Override
              public void widgetDefaultSelected(SelectionEvent event) {
                IStructuredSelection sel =
                    (IStructuredSelection) availableLangViewer.getSelection();
                if (!sel.isEmpty()) {
                  moveAcross(
                      availableLangViewer,
                      selectedLangViewer,
                      Common.makeGenericList(NSISLanguage.class, sel.toList()));
                  selectedLangViewer.reveal(sel.getFirstElement());
                  langRunnable.run();
                }
              }
            });
    selectedLangViewer.addSelectionChangedListener(
        new ISelectionChangedListener() {
          public void selectionChanged(SelectionChangedEvent event) {
            leftButton.setEnabled(mse.canEnable(leftButton));
            allLeftButton.setEnabled(mse.canEnable(allLeftButton));
            upButton.setEnabled(mse.canEnable(upButton));
            downButton.setEnabled(mse.canEnable(downButton));
            selectLang.setEnabled(mse.canEnable(selectLang));
            if (displaySupported != null) {
              displaySupported.setEnabled(mse.canEnable(displaySupported));
            }
          }
        });
    selectedLangViewer
        .getList()
        .addSelectionListener(
            new SelectionAdapter() {
              @Override
              public void widgetDefaultSelected(SelectionEvent event) {
                IStructuredSelection sel = (IStructuredSelection) selectedLangViewer.getSelection();
                if (!sel.isEmpty()) {
                  moveAcross(
                      selectedLangViewer,
                      availableLangViewer,
                      Common.makeGenericList(NSISLanguage.class, sel.toList()));
                  availableLangViewer.reveal(sel.getFirstElement());
                  langRunnable.run();
                }
              }
            });

    m.updateSlaves();

    listsComposite.addListener(
        SWT.Resize,
        new Listener() {
          boolean init = false;

          public void handleEvent(Event e) {
            if (!init) {
              // Stupid hack so that the height hint doesn't get changed
              // on the first resize,
              // i.e., when the page is drawn for the first time.
              init = true;
            } else {
              Point size = listsComposite.getSize();
              GridLayout layout = (GridLayout) listsComposite.getLayout();
              int heightHint = size.y - 2 * layout.marginHeight;
              ((GridData) availableLangList.getLayoutData()).heightHint = heightHint;
              ((GridData) selectedLangList.getLayoutData()).heightHint = heightHint;
              int totalWidth = size.x - 2 * layout.marginWidth - 3 * layout.horizontalSpacing;
              int listWidth = (int) (totalWidth * 0.4);
              int buttonWidth = (int) (0.5 * (totalWidth - 2 * listWidth));
              size = availableLangList.computeSize(listWidth, SWT.DEFAULT);
              int delta = 0;
              if (size.x > listWidth) {
                delta = size.x - listWidth;
                listWidth = listWidth - delta;
              }
              ((GridData) availableLangList.getLayoutData()).widthHint = listWidth;
              ((GridData) buttonsComposite1.getLayoutData()).widthHint =
                  totalWidth - 2 * (listWidth + delta) - buttonWidth;
              ((GridData) selectedLangList.getLayoutData()).widthHint = listWidth;
              ((GridData) buttonsComposite2.getLayoutData()).widthHint = buttonWidth;
              listsComposite.layout();
            }
          }
        });

    addPageChangedRunnable(
        new Runnable() {
          public void run() {
            if (isCurrentPage()) {
              selectLang.setEnabled(mse.canEnable(selectLang));
              if (displaySupported != null) {
                displaySupported.setEnabled(mse.canEnable(displaySupported));
              }
            }
          }
        });

    mWizard.addSettingsListener(
        new INSISWizardSettingsListener() {
          public void settingsChanged(
              NSISWizardSettings oldSettings, NSISWizardSettings newSettings) {
            enableLangSupport.setSelection(newSettings.isEnableLanguageSupport());
            m.updateSlaves();
            selectLang.setSelection(newSettings.isSelectLanguage());
            if (displaySupported != null) {
              displaySupported.setSelection(newSettings.isDisplaySupportedLanguages());
            }
            java.util.List<NSISLanguage> selectedLanguages = newSettings.getLanguages();
            java.util.List<NSISLanguage> availableLanguages =
                NSISLanguageManager.getInstance().getLanguages();
            if (selectedLanguages.isEmpty()) {
              NSISWizardWelcomePage welcomePage =
                  (NSISWizardWelcomePage) mWizard.getPage(NSISWizardWelcomePage.NAME);
              if (welcomePage != null) {
                if (!welcomePage.isCreateFromTemplate()) {
                  NSISLanguage defaultLanguage =
                      NSISLanguageManager.getInstance().getDefaultLanguage();
                  if (defaultLanguage != null && availableLanguages.contains(defaultLanguage)) {
                    selectedLanguages.add(defaultLanguage);
                  }
                }
              }
            }
            selectedLangViewer.setInput(selectedLanguages);
            availableLanguages.removeAll(selectedLanguages);
            availableLangViewer.setInput(availableLanguages);
          }
        });
  }