I may be completely misunderstanding wall priorty here but - I have a demo layer, set to a low priority (20) and a new wall layer, set to a higher priority (5), which in most instances they clean up amongst themselves, and the demo ignores the new wall and vica versa, however, there are one or two places in the drawing where the demo walls are cleaning up with the new walls, and I cant figure out how to stop that.
There anyway to have the demo walls automagically clean up, but ignore the new / existing walls that they contact?