Environments / Variables not able to be referenced in GraphQL text editor

I have created an environment and added some variables.

The variables are created correctly because I can reference them in the address bar when I type CTRL-Space per the Yaak documentation.

In the GraphQL editor I have a Query typed out. I now want to abstract some of the strings to reference the Environment Variables. When I type CTRL-Space nothing happens in the context of the GraphQL editor so it does not appear to be possible to embed Environment Variables in a GraphQL query.

Example Query:

{
  authenticate {
    username_and_password(
      username: "REPLACE_ME",
      password: "REPLACE_ME"
    )
    {
      token
    }
  }
}

I want to reference Environment Variables in the areas that currently say REPLACE_ME.