Roadmap view enhancements: multi-level roadmap visualization (with possibility to expand/collapse levels)

Current Limitation

Roadmaps currently support only two levels of visualization (swimlanes and cards). This restricts the ability to represent hierarchical structures beyond the top-level items, forcing users to switch between list views and multiple roadmaps to understand dependencies and details.

Proposed Enhancement

Enable hierarchical expansion within roadmap views, similar to the list view. This would allow users to:

• Expand parent entities (e.g., portfolio epics) directly in the roadmap.
• Display underlying child entities (e.g., epics, features, stories) with their planned start and end dates.
• Collapse or expand levels dynamically, giving flexibility in how much detail is shown.

By enabling hierarchical expansion in roadmaps, users gain a consistent overview across portfolio epic, epic, and feature levels, keeping parent and child entities visually connected. This provides clarity on timelines, flexibility to show the right level of detail, and efficiency by eliminating the need to switch between multiple roadmaps.

Example Use Case

I am leading a portfolio, and I have a roadmap consisting on the portfolio epics in my portfolio, with planned start and end date. To get more detail of the underlying epics and features, I'd like to expand the portfolio epic like I can do in a list view and showing the roadmap of the underlying entities. Then I see which child issues that are planned/Unplanned together with their roadmap, potential planning conflicts that affects the overall progress of the portfolio epic.