I've found this feature, this feature and this question asking to open certain links in new tabs.

I'm assuming this has already been implemented because whenever I click a link in the main menu it opens in a new tab.

I find this highly annoying and was hoping someone could tell me a way to disable it. I don't want to close 20 tabs just because I clicked some navigation links. Besides, there's always the middle mouse button or Ctrl+click if you really want to open a link in a new tab.

Never mind, I found it: the command sudo openproject config:set OPENPROJECT_HTTPS=true fixed it for me.

Thank you for providing an update on your solution, Sam!