Wave users can easily view milestones (or actions, activities, or attachments) associated with initiatives, also known as parent/child relationships, in Gantt chart view. By filtering, sorting and grouping your data, you can see all your cards that are on hold, view cards that have been updated, or easily identify those that require leadership attention.
To open or close all initiatives in the view, click on the Collapse all/Expand all icon as illustrated below. Wave will also show each category of child card (e.g. milestones, actions, or activities) by clicking in the card structure panel.
You can click on a parent initiative individually to show or hide the child cards.