I kind of assumed that (non-milestone) subprojects should show up on the parent's board as columns.
Is that an existing feature that I can't find?
Should we support that?
Should it be optional or just always on?
Blocking stuff that deserves a fix:
- a Workboard never shows duplicate Tasks, but a Task can be attached to multiple sub-projects, so we cannot just display sub-projects as additional columns (note: Milestones does not have this problem)