Epic "Tree" tab does not render a tree for epics without sub-epics

Problem to solve

The "Tree" tab in the Epic page renders a tree when the epic contains sub-epics:

When the epic does not contain a sub-epic, no "Tree" is rendered:

This is confusing from a UX experience because the tab name does no longer represent the content accurately.

Further details

Proposal

• We could rename Tree to Issues when the epic has no sub-epics
• We could create a separate Issues tab that always contains the replicated issues
• The Tree tab could always contain the entire tree for this epic until the last common ancestor and only expand the branch that contains the epic

Permissions and Security

Documentation

Testing

What does success look like, and how can we measure that?

Links / references