@Nullable JComponent getFileLevelComponent(@NotNull FileEditor fileEditor) {
    if (fileLevelComponentsStorage == null) {
      return null;
    }
    else if (fileLevelComponentsStorage instanceof Pair) {
      //noinspection unchecked
      Pair<FileEditor, JComponent> pair = (Pair<FileEditor, JComponent>)fileLevelComponentsStorage;
      return pair.first == fileEditor ? pair.second : null;
    }
    else if (fileLevelComponentsStorage instanceof Map) {
      //noinspection unchecked
      return ((Map<FileEditor, JComponent>)fileLevelComponentsStorage).get(fileEditor);
    }
    else {
      LOG.error(new IllegalStateException("fileLevelComponents=" + fileLevelComponentsStorage));
      return null;
    }
  }
@Nullable JComponent getFileLevelComponent(@NotNull FileEditor fileEditor)