private void updateEditor() {
    Object source = getSource();

    String fileName = "Dummy." + (source instanceof FileType ? ((FileType)source).getDefaultExtension() : "txt");
    LightVirtualFile lightFile;
    if (source instanceof PsiViewerExtension) {
      lightFile = new LightVirtualFile(fileName, ((PsiViewerExtension)source).getDefaultFileType(), "");
    }
    else if (source instanceof LanguageFileType) {
      lightFile = new LightVirtualFile(fileName, ObjectUtils
        .chooseNotNull((Language)myDialectComboBox.getSelectedItem(), ((LanguageFileType)source).getLanguage()), "");
    }
    else if (source instanceof FileType) {
      lightFile = new LightVirtualFile(fileName, (FileType)source, "");
    }
    else {
      return;
    }
    EditorHighlighter highlighter = EditorHighlighterFactory.getInstance().createEditorHighlighter(myProject, lightFile);
    try {
      myEditor.setHighlighter(highlighter);
    }
    catch (Throwable e) {
      LOG.warn(e);
    }
  }
private void updateEditor()