String childId = child.getId();
for (ComponentPageElement existing : children)
{
if (existing.getId().equalsIgnoreCase(childId))
throw new TapestryException(StructureMessages.duplicateChildComponent(this, childId), child,
new TapestryException(StructureMessages.originalChildComponent(this, childId,
existing.getLocation()), existing, null));
}
children.add(child);
}