After reading a couple of Firefox Multi-Account Containers instructions on on how to use, which I gave a positive Yes if it was helpful, I find I cannot get any website to open in a container. I've use nightly for 5 - 6 months?? I update Nightly almost daily. Gave Firefox testteam permission to install test automatically. Only thing I ever got was the original test version of containers. So installed the production version today. Do not find any right or left mouse button click to provide any accept to open a tab or a new tab in a container. Hold does not work. Spent last 45 minutes with no success. Moving on may attempt again or remove nightly, install production version with containers and see if that works.