Steps to reproduce:

1. Create a new job
2. Select Git as SCM
3. In the credentials section, click on Add, configure a Secret Text credential (I used a github account)
4. On the Job Configure page, you'll see that the Credentials dropdown is still none. The newly created credential doesn't show up.

Issue marked as critical since there is no way I can setup Jenkins to work with Git. If there are workarounds, please let me know.