Classic - cannot configure Rank field for project

Problem

Both in project specific configuration and global configuration.

A project that had a field which was then removed was not able to be configured again.

To reproduce:

• Create a sample scrum project
• Go to classic mode
• Click Tools > Configuration
• Look at Rank field - no way to add a new one

In test data, e.g. QuickFilters project, there is a field listed. It can be removed, then you get to the same state where you can't add another one.

Cause

As of JIRA 6.0, the class CalculatedCFType, from which our RankCFType class extends, is no longer a SortableCustomField. This causes Classic configuration to not recognise the rank field as a valid option.

Work-around

The Rank field is still able to be used for projects which use the Scrum Project Template. If you can alter your project's configuration to use this template instead, then you should be able to use the Rank field.