There's a bug with global landmarks

[sebjameswml]

If you delete one, then re-add it, then you may end up with a /global_landmarks object in the h5 which doesn't have ALL the global landmarks present on each slice.

[sebjameswml]

I just tested deleting and re-adding the first of 3 global landmarks. It works, but the newly added GLM becomes GLM3 with the original GLM2 and GLM3 becoming GLM1 and GLM2.