Right sidebar's collapse button is at the bottom, while the left sidebar's collapse buttom is at the top

Problem to solve

The placement of our sidebars' collapse buttons is inconsistent. The left sidebar's collapse button is at the bottom of the sidebar, while the right sidebar's collapse button is at the top:

Additionally, the buttons use different icons, which already has an issue here: https://gitlab.com/gitlab-org/gitlab-ce/issues/45109.

Proposal

Make the sidebars look and behave the same.

One idea: Add the Collapse behavior to the bottom of the sidebar across issuables.

• Sidebar content scrolls under the collapse item.
• Collapse item is fixed.
• Copy on this could be tweaked. Maybe we could just say Collapse throughout and omit sidebar.

IE:

Issues	Incidents

This should also apply to epics, requirements, MRs- anywhere with this sidebar.

Further details

If we move the collapse button on the right sidebar to the bottom, we need to make sure it's fixed so that it's always accessible, even if the sidebar has a scroll bar.

Links / references