<BUG>protected Callback<VChild, Void> copyChildCallback()</BUG><CONTEXT>private ContentLineStrategy contentLineGenerator;protected void setContentLineGenerator(ContentLineStrategy contentLineGenerator){this.contentLineGenerator = contentLineGenerator;}<extra_id_0>{throw new RuntimeException("Can't copy children.  copyChildCallback isn't overridden in subclass." + this.getClass());};</CONTEXT>
protected Callback<VChild, Void> copyIntoCallback()