Sometimes, we might have duplicated issues regarding the same subject. Normally we found this after someone charge some time on it. If we close an issue and stays with the other duplicated, we lost the time charged in the closed issue. We could have a feature that allows us to merge the logged hours into the main issue when we relate issues to each other. This could be optional, meaning we can simply relate the issues or do a "merge" between them, which will make the related issue to be closed as "duplicated" and migrate the hours to the main issue.