Inspire Planner users are able to set their view type for the Portfolio Lightning Web Component (LWC). Users can choose what is displayed under projects, either milestones only or parent tasks.
To enable this feature in your Saleforce org, please see Admin Guide - Portfolio LWC - Portfolio View (Milestones or Parent Tasks).
As a default, when a user creates a portfolio or opens it for the first time, the default view is set to "Milestones Only". This means that when you expand projects, it will only display the milestones underneath.
Each user can then choose their view preference by selecting either "Milestones Only" or "Parent Tasks". When a user selects "Parent Tasks", then all parent tasks under a project are displayed in the portfolio.
The parent tasks will be displayed with the same indentation as they appear within the project.
The view type is saved in the user preferences record. A user preferences record is automatically created for each user that views a portfolio. The user preferences record contains the user's viewing preferences such as columns displayed/hidden, column order, expanded/collapsed rows, and the view type. This means that every time the user opens the same portfolio, it will display according to the user preferences record.