Revert "Build null nodes if selections are empty."

This reverts commit 654e5d747f07dfa1f900a76e5f5bbe8cff9da184.
Revert "Avoid another null reference."

This reverts commit 99aca8339cfe21d9fa117dd04050595359bccb67.
Revert "Avoid null reference when processing element lookup."

This reverts commit cf03d378314e0303a3f62f6339acd3a794beed70.