Option to link variable group missing

According to the Microsoft docs, I should see an option to link to a variable group under the Variables tab in my build definition, but I don't see it.

I have a variable group defined, but Link Variable Group option does not show up. I'm using Microsoft Visual Studio Team Foundation Server Version 15.112.26301.0.

Solution

Your screenshot is referencing "Build" variables, however the documentation you reference is "Release" variables. These are two completely different setups in VSTS.

However, the ability to link variable groups in is worked into both Builds and Releases now from within VSTS. The screenshot below is from one of my build definitions while I am editing it.