code: function mergeChildren( from, into, refNode, forward ) {
  		var child, itemDir;
  		while ( ( child = from[ forward ? 'getLast' : 'getFirst' ]( elementType ) ) ) {
  			if ( ( itemDir = child.getDirection( 1 ) ) !== into.getDirection( 1 ) )
  				child.setAttribute( 'dir', itemDir );
  
  			child.remove();
  
  			refNode ? child[ forward ? 'insertBefore' : 'insertAfter' ]( refNode ) : into.append( child, forward );
  		}
  	}
docs: Merge child nodes with direction preserved. (#7448)