Internal id and birth/death dates cannot be blanked in pedigree editor
1) create a patient record and enter some value in external id field (and/or birth/death datefields)
3) open pedigree editor and delete the value entered in step 1
4) save pedigre
5) close pedigree
6) observe the patient record -> the original value is still there
Note: This anomaly only happens in Pedigree editor when the external id (or date) is blanked out. I if put a different value into the field, the new value does get saved.