[Update 7th Feb, 2019] A fix for this is now rolled out to all rings so it should be working as expected.
If you are wondering why clicking on edit in the test plans directory page is not working, it’s a recent regression that we are working to get hotfixed as soon as possible. So if you navigate to the test plans directory page and try to click on Edit, nothing happens:
If you open the browser console you will see an error that says,
Failed to load resource: the server responded with a status of 404 (): https://cdn.vsassets.io/v/M146_20190204.13/_scripts/TFS/debug/VSSUI/ResponsiveViewport.js
We have fixed the issue at our end and our waiting for the change to rollout with TFS deployment. Meanwhile, if you’d like the issue mitigated immediately please reach out to devops_tools at microsoft dot com, with your organization name.