Items can be assigned to layers, and layers can be hidden, locked or moved up/down in the Z order as a group. Layer objects provide Visible, Locked, and ZIndex properties, which will affect all items in the respective layer. Layers also expose a Title property. Newly drawn items are added to the layer specified via Diagram.ActiveLayer.

Set the LayerIndex property of items to associate them with layers in the Diagram.Layers collection. If LayerIndex has the default value of -1, the item is not associated with any layer and its visibility depends only on the item's own Visible property.