Last time I checked, the site-specific container extensions (Facebook and Google) had a "don't open anything except the target site in the container" feature th

Last time I checked, the site-specific container extensions (Facebook and Google) had a "don't open anything except the target site in the container" feature that appeared to be missing from the multi-account containers extension. I agree that the best solution would be to add that functionality to the base extension rather than create a specific extension for every site people might want to block.