Adding a genotype that has a status of "Tested Negative" or "Rejected Candidate" on the patient form causes the pedigree editor to break for that patient. Their information form modal will be un-openable. This was introduced in PT 1.4.2, once "Negative" gene status changed to "Tested negative". Hence, the master branch of PT has this bug.
Repro:
See http://172.20.4.77:8080/P0000001
Create a patient, add any gene with a status of "Tested negative" or "Rejected candidate"
Add a pedigree, and try to open the patient form. Observe the error in the console.
As a side note, the automated tests did not catch this earlier as I only added a "Tested negative" or "Rejected candidate" gene status in the matching tests.