Save button disabled when configuring JDBC data source

Hello,

I have an existing data source that was missing JDBC driver selection after migration to a new server. When I selected proper JDBC connection and tested it using the test button, it worked fine, and I got "login successful message". However, I cannot save these changes as the "save" button remains disabled (grayed out). I successfully did it for another data source previously. I am wondering if there is some kind of lock on a data source so that it cannot be modified? Or is there any other reason why I cannot save changes?