A hierarchical schematic design editor displays mask layers for each shape as mask specific colors and alerts a user to mask layer conflicts during the design and editing process. According to an embodiment, mask colors may be assigned at the time the shapes or geometries and cells are placed in a circuit design layout, or when a mask layer condition indicating that two or more shapes should be set to different mask layers is detected. In an embodiment, if the distance between two shapes is less than a predetermined threshold, those shapes may cause a mask layer condition. Shapes may be grouped to facilitate mask layer condition detection and mask layer assignment.