Index: obj_arc.c
===================================================================
--- obj_arc.c	(revision 28841)
+++ obj_arc.c	(revision 28842)
@@ -63,8 +63,8 @@
 	if (layer->parent_type == PCB_PARENT_UI)
 		return;
 
-	assert(layer->parent_type == PCB_PARENT_DATA);
-	pcb_obj_id_reg(layer->parent.data, arc);
+	if (layer->parent_type == PCB_PARENT_DATA)
+		pcb_obj_id_reg(layer->parent.data, arc);
 }
 
 void pcb_arc_unreg(pcb_arc_t *arc)