This feature is available to all users
When you are inside a project, you can collapse or expand the list of projects by clicking the three lines icon in the top left corner.
The left sidebar is only shown inside a project
The left sidebar appears when you open a project board. It is not shown on the Projects page. If you prefer the classic Projects page, select the ... menu next to the Projects title, then select Switch to classic view. See Switch to the classic Projects page.
To collapse or expand the left sidebar
- Navigate to a Project.
- Click the three lines icon in the top left corner (keyboard shortcut: M).