Enable Dark Feature in Jira
Platform Notice: Server and Data Center Only - This article only applies to Atlassian products on the server and data center platforms.
Some of the features in JIRA are not enabled by default (there could be many reasons for that) and implemented as a Dark Features.
You should be very careful with those features and should change it when you explicitly asked by Atlassian support.
To enable/disable Dark Features you need to be JIRA admin. First, go to the page: <Jira_URL>/secure/SiteDarkFeatures!default.jspa .
In order to enable a feature flag, type <feature_flag_name>.enabled in the "Enable dark feature" textbox and click the "Add" button. Make sure to not have double ".enabled" suffix at the end of feature flag name.
To disable a feature flag, either click "Disable" link next to a feature flag in the "Enabled dark features" section (as on a screenshot below) or type <feature_flag_name>.disabled feature flag in the "Enable dark feature" textbox and click the "Add" button. Make sure to not have the combination of suffixes - ".enabled.disabled" - at the end of the feature flag name.