Because I'm unaware of any documentation on this anywhere else (the CR part is that there should be): some day, I'm going to gather an exhaustive, ordered list which will establish where everything fits in this priority list so that we have one more tool on our troubleshooting belt.
From what I'm seeing, horizontal feature constraint is sought prior to the application of parametric constraint.
I intend to update this as other folks and my own encountering stumbling blocks provide more. But for today, just these two matter to me:
- Seek horizontal feature definition
- Location of point by parametric constraint