This has got to be a bug. There should be an option within designer to use example values rather than variable names. Otherwise the design view is quite misleading.
You’d still see the variable name in the design popup, just not on the preview behind it.
You’d be able to toggle that preview between using real data vs variable names.
It would make the design process so much quicker by getting a live refresh rather than a 3 second refresh in a second browser window. Seems like a small 3 seconds but it’s not.