Currently, when by-project breakdown is used in 'Spent time', information about projects' hierarchy is lost. This is valuable information, and an ability to see it in the report will improve usability of the report.

As example, the same hierarchy is shown in 'Administration > Projects'.

Suggested design:

Make the feature optional (for backwards compatibility and for users already depending on the current report structure).¶

When enabled, show the hierarchy in the same way it is currently shown on the 'Administration > Projects' page.¶

When enabled, show 'Hours' value for aggregate projects (then ones containing other sub-projects) in grey (in the same way it is currently done in the report when multiple levels are used).¶

A problem can arise, however, when an aggregate project contains some hours reported directly into it (in that case, 'grey' values will not be always just a sum of its sub-nodes). I think it is still Ok to just show these values in grey color, regardless, without any extra mark-up.