I am following the Pipes HDA tutorial for Unreal Editor and I have my pipes mesh showing up in the Unreal Engine. But when I drop the curve1 node into the Editable field of the Type Properties window and save and reload the HDA in UE4 I have no option to extend the curve as shown in the video tutorial @ 6:08 time code.
https://vimeo.com/210679269 [vimeo.com]

Is there some other selection node I have to use to verify my curve is indeed editable inside the Unreal Editor 4.2.1?

Hi,
What version of Houdini/the plugin are you using?
This regression was introduced recently, and fixed in H17.0.408

I am using H17.0.407. Unreal Engine 4.2.1.

Yep, Houdini Build 17.0.411 fixed it. I can see and edit my curve.