症状

The Issue Operation Buttons (like Edit, Comment, Assign, More, and Transition) are not displayed when viewing any issue in a JIRA instance.

原因

The "Issue Operation Plugin" System Add-ons is Disabled

ソリューション

1. Navigate to JIRA Administration > Add-ons > Manage Add-ons.

2. Change the add-ons category from User-Installed to System.

3. Search for Issue Operations Plugin.
4. Enabled back the Plugin.