Colonelkeds

I am trying to learn CA Interiors X9 trial version. We do very custom cabinets and have a lot of unique situations, which led me to CA Pro. I want to use the program primarily as a visualization tool for my clients.

I am trying to butt an 18" deep x 20" high base (window seat) with 6" clipped corner against a 12" deep tall bookcase cabinet, but as soon as the cabinets touch, the clipped corner becomes squared. It comes back when cabinets are moved 1" apart. I tried a 1" filler, but the clip disappears then as well. How can I make this work? I also want a clipped countertop to die into the bookcase. Can this be done?