WorldEditor’s “Make Draped Polygons” feature is a stop-gap and a hack, and someday it will be replaced with something better.
I mention this as I debug it because there are feature requests in the bug base to enhance its operation; I think I will replace it with a more fundamentally useful (and less awkward) interface before adding more functionality.
“Make draped polygons” was born out of a hack to WED to allow Sergio to finish his LOWI custom scenery pack before WED 1.1 was even public beta. In other words, it was a crude attempt to get draping into WED before the real UI work was done.
I am resisting the urge to nuke the feature now because there isn’t something to replace it yet. But in the long term, what WED needs is better tools to work with imagery and manage the text files that are needed to create ground imagery around an airport.
This new UI will be after the 1.2 release; for now the goal is to get 1.2 stabilized and finalized.