Create/Modify Custom Beam Sections

I am creating a custom I Beam section but the input fields are constantly being locked, preventing me from updating the dimensions. Restarting the application and going straight to the Beam Section Library sometimes, but not always let me update the dimensions. However, that doesn't seem to be working today. I have restarted the application several times but still can not create/edit beam sections. Under what conditions is the beam section library locked?