Portfolio: gannt revealing detail from multiple board sources

We need to portfolio gannt view to display granular detail from project board items and sub-items, as we can do with a dashboard. For the portfolio feature, the gannt chart view is far less useful than a dashboard with a standard dashboard widget. A dashboard allows us to display tasks and sub-tasks from multiple boards. This is a massive gap for the portfolio feature, which only displays single timeline blocks for each project board. Conceptually, with aportfolio aiming to provide an overview of all projects, this gannt needs to be improved to match the dashboard widget capability.