/src/main/java/org/htmlunit/html/HtmlElement.java
&& HtmlPage.isMappedElement( htmlPage, qualifiedName) ; final boolean mappedElement = isAttachedToPage( )
final boolean mappedElement = isAttachedToPage ( ) && HtmlPage.isMappedElement ( htmlPage, qualifiedName ) ;
} @Override public Attr setAttributeNode(final Attr attribute) { final String qualifiedName = attribute.getName(); final String oldAttributeValue = getAttribute(qualifiedName); final HtmlPage htmlPage = (HtmlPage) getPage(); <extra_id_0> if (mappedElement) { htmlPage.removeMappedElement(this); } final HtmlAttributeChangeEvent event; if (ATTRIBUTE_NOT_DEFINED == oldAttributeValue) { event = new HtmlAttributeChangeEvent(this, qualifiedName, attribute.getValue());