Document how Ranking works when issues are moved to an Empty Sprint/Backlog

Summary

When an issue is moved to an Empty Sprint/Backlog in the backlog mode of a Scrum board, the Rank value of the issue is unchanged because there's no issue to be compared with it the Sprint/Backlog where it's moved to. However, this is not documented anywhere.

Suggestion

This should be documented clearly, otherwise confusion might be encountered when one views the board's filter query in Issue Navigator, in which the order of the issues might not be the same top-down order as what he/she sees in the backlog mode. A KB article has been created for this at:

• Why an issue's Rank value is not changed when moved to an Empty Sprint/Backlog