When opening a google link from facebook container, two tabs get open.

[tombuben]

Same thing happens the other way around or with other forks of facebook container, so the issue is probably a bit more broader.

Common issue with another fork: v1shwa/contain-twitter#6

[robcee]

see also: https://github.com/mozilla/contain-facebook/issues/636

[bolokanar]

This is a pretty annoying bug and needs to be finally looked into.