For the record, sidebar was made not collapsible in 15.1 release because with promoted trackers & kanban, it was no longer possible to have a consistent and usable sidebar when collapsed.
It turns out that in some situations, users want to maximize the area available for content, hence usage of collapsed sidebar.
Collapsible sidebar is back with:
- Platform small logo at the top, like original collapsed sidebar
- Tuleap small logo at the bottom, like original collapsed sidebar
- Services are no longer displayed at all
- The expand button is always displayed, bellow the top logo.
- Size of the sidebar is kept to 50px, like original collapsed sidebar
When the sidebar is expanded, there is a collapse button at the top, hidden by default, that appears on hover:
https://www.figma.com/proto/OMsELWpYKTarzLIgXgsIP1/Welcome-and-Retain?page-id=3754%3A41370&type=design&node-id=3754-95307&viewport=45%2C464%2C0.19&t=gNnV20YGudv7njDq-1&scaling=min-zoom&mode=design