@Override
  public boolean isApplicable(@NotNull final PsiElement element) {
    return element instanceof PsiFile &&
           ((PsiFile)element).getVirtualFile() != null &&
           !NestingTreeStructureProvider.getFilesShownAsChildrenInProjectView(element.getProject(),
                                                                              ((PsiFile)element).getVirtualFile()).isEmpty();
  }
@Override
  public boolean isApplicable(@NotNull final PsiElement element)