Redmine

Hi. I am using Bitnami Redmine 2.5.1.

I have created a custom filed "Close Status". And I configured that custom filed as "Required" when the issue status is Closed & Rejected. This configuration is displayed as red asterisk mark in issue editing page. But this rule is not forced to users, when they try to change issue status "Closed", without input "Close Status" (required field) and click "Save" button then the issue saved without that "Close Status' required field.

Is this some kind of defect? or Is there any missing configuration for this matter?