While the extension is incredibly useful, it has some glaring omissions.
For some inexplicable reason, once you set a container as default for a website, you can never clear that default again, at most you can change it, but if you have multiple containers for different accounts on that same website, whenever you are browsing it and want to open a link in a new tab, it will always, at the very least, prompt you to open on the "default" container, which is incredibly annoying.
Another incredibly annoying thing is that you can't truly sort your containers, they will always be on the order they were created. And whenever you reinstall Firefox, or install on a new device, and need to reinstall your extensions, including this, the containers will again, be in the same order they were created, and even if you sort them to your taste when clicking on the extension icon, in the "Open Link in New Container Tab" context menu, they will always be in the wrong order.
Please fix this, devs.