Gap between dormer and roof

[JasAbell]

Hello! I'm new to Home Designer. I'm trying to add an auto dormer to a 12:12 pitch roof attic space. As you can see in the attached picture, I have a gap between the dormer and the roof. I assume this is some simple setting, but I'm too new to know. Why do I have the gap between the dormer and the roof?

 

I am using Home Designer Pro 2024 on a MacBook Pro. The second story roof is set to ignore top (2nd) floor. The interior walls are set to knee walls.

 

Thank you!