@Bouscram
Thank you for your kind words.
The reason for this is that I haven’t implemented it yet. 
I’m currently working on final bug fixes for the “other parents” expanders. They don’t address your point, but they already partially cover some of the changes needed to show the parents of the spouse of the active person.
Take a look at the screenshot below.
Where should the children of “Jordan, William” go? I can only think of the position of the blue circle. This would cause the line connecting them (the red connection) to intersect the existing (black) connection.
I can do that. I’ll add it to my list.