Cyncly and the manufacturers have added many rules to prevent many illegal configurations. While these rules are extensive and well-tested, they are not a substitute for product knowledge.
Ultimately the designer is responsible for building legal configurations.
Both fundamental and catalog-specific construction rules are enforced (such as no stacking on top of 10" element, total stack height restriction, etc.). If, for example, you place an element that exceeds that maximum panel configuration height, you will see an Alert dialog appear. If you do not wish to see this type of dialog, you can disable it through the View menu, Design Alerts.
A fundamental Panel Builder rule is that tile elements must begin and end at tile seams. If a 7” high tile is placed at the bottom of Side 2, a Design Alert appears. This is because the base frame is defined with a 14” high tile seam. So a 14” high tile can be placed at the base, or as was done with the fabric tile on Side 1, another tile that aligns with another higher tile seam.
In addition to Design Alerts, Panel Builder sometimes displays a warning message when an element is placed. For example, if a Markerboard tile is added to the Side 1 stacking frame. This is a legal operation; however, since adding a tray to the markerboard tile would collide with the stacking seam, a warning message is displayed. Ignoring such messages will result in invalid configurations.
Some property changes reset the entire configuration. In the example below, changing the height of the base frame causes all the tiles and stacking frames to be removed. This assures that all element placement rules are run.