That isn't how I got the designer context. I used some code from this forum post.
As pturmel noted,
so tread carefully and probably don't use this in a production setting. I used it to partially automate some mass tag renaming I was very closely supervising. I wouldn't trust it for much more than that, and I certainly wouldn't trust it across Ignition versions.
In the forum thread I linked you will also see @Robert.McKenzie warn against relying on this sort of implementation, so consider this a double warning.