Hello   I have the following problem. I draw a building level 0.? Than I make a viewport from level 0 and put this on my level -1. By this way I can control the classes in the viewports and make my walls from level 0 visible with other attributes so I don't give a color to the wall and the linetype dashed. In this way when I make changes in my level 0, it will be updated in my level -1 But when I make a section on that building, I see all the walls from my level 0 in my level -1 e