STR:

• Create a freestyle job.

• Navigate to configure and select "Use secret text(s) or file(s)" under Build Environment.

• Click "Add" for the Jenkins credential.

• The Jenkins Credentials Provider: Jenkins UI box will appear.

• Click the "Cancel" button and you can see that this does not work.

Expected: Dialog window closed when Cancel button clicked

Workaround: Esc button closes the dialog window.

Note: It's a prototype.js removal regression.