Consider using an expandable tree to show objectives in period summary

Currently, there is a "show objectives" toggle in the group summary pane(s) in the period summary view, to allow the specific objectives to be displayed underneath each group.

It would be possible to use a tree for this instead, so that the user could expand individual groups to see the objectives. Angular Material has a tree component:

https://material.angular.io/components/tree/overview

The advantage of this would be that the user could easily open and close individual groups of interest. Currently, it's easy to lose your scroll position when you turn on the "show objectives" toggle, especially if there are a lot of groups and/or objectives.

The disadvantage of using the standard Angular Material tree component would be that the view would become much less information-dense: each tree node is much taller than an individual list item.