Campaign Switcher
When viewing a campaign, the campaign’s name is clickable in the top of the sidebar. This opens up the campaign switcher.
First it shows campaigns you are a member of, followed by campaigns you are following.
The last option is to create a new campaign.
Changing the order
By default, campaigns appear in the order of you joining/following them. This can be change in your appearance settings. The option is called Campaign switcher default order.