Hi bev77!
This is actually from an error in how the related post was built out.
TestComplete will truncate the 'Values' to save screen real estate, this means the code snippet in the linked doc is technically incomplete.
Below is what TC will show you of that code expression once you have clicked out of it, notice that it matches the doc;
Though if we click on the 'Value' for the textBox step, we see the entire value =
The correct code expression should be = 'KeywordTests.Test1.Variables.Random(....'
Essentially we are missing the location of the variable in the image that is present in the linked doc.
Sorry for the confusion, I hope this helps to clear things up!
