@Override
  public boolean canFindUsages(@NotNull final PsiElement element) {
    if (!element.isValid()) {
      return false;
    }
    if (element instanceof PsiFileSystemItem) {
      return ((PsiFileSystemItem)element).getVirtualFile() != null;
    }
    return LanguageFindUsages.canFindUsagesFor(element);
  }
@Override
  public boolean canFindUsages(@NotNull final PsiElement element)