I can't create a test case from the UI, when I have Create Test Case permission.

1. As a Project Lead, I assign User1 permissions to Create Test Case via Settings>Zephyr Scale>Permissions>Test Cases> Create.   

2. As User1, I click Tests>+New> and create my test case

But the problem is the Save button is greyed out.  It does not un-grey unless I have Edit Test permission.