Once the Jenkins environment has updated to a version of Firefox > 45, re-enable the bok-choy test that is currently skipped: https://github.com/edx/edx-platform/blob/master/common/test/acceptance/tests/studio/test_studio_outline.py#L119
Hopefully it will pass. Otherwise, we might have to re-write the test entirely to regain the coverage.
We narrowed down the issue to a change the RET team introduced to the course outline header which added <br> elements. Removing that change makes the test pass in jenkins: https://github.com/edx/edx-platform/pull/16682
We tried to do the linebreaks in CSS instead of using <br> elements, but that did not make the test pass in jenkins: https://github.com/edx/edx-platform/pull/16695
If we run the test in Chrome, it passes. If we try running the test in a recent version of Firefox (e.g. devstack's firefox 54) we get an unrelated error that the driver does not support mouseMoveTo.