app/code/local/Aoe/Layout/Model/Layout.php
protected function processOutputAttribute(Mage_Core_Model_Layout_Element $node)
    {
        if (isset($node['output'])) {
            $blockName = (string)$node['name'];
            if (empty($blockName)) {
                return;
            }
            $method = trim((string)$node['output']);
            if (empty($method)) {
                $this->removeOutputBlock($blockName);
            } else {
                $this->addOutputBlock($blockName, $method);
            }
        }
    }
protected function processOutputAttribute(Mage_Core_Model_Layout_Element $node)
    {
        if (isset($node['output'])) {
            $blockName = (string)$node['name'];
            if (empty($blockName)) {
                return;
            }
            $method = trim((string)$node['output']);
            if (empty($method)) {
                $this->removeOutputBlock($blockName);
            } else {
                $this->addOutputBlock($blockName, $method);
            }
        }
    }
protected function processOutputAttribute ( Mage_Core_Model_Layout_Element $ node ) { if ( isset ( $ node [ 'output' ] ) ) { $ blockName = ( string ) $ node [ 'name' ] ; if ( empty ( $ blockName ) ) { return ; } $ method = trim ( ( string ) $ node [ 'output' ] ) ; if ( empty ( $ method ) ) { $ this -> removeOutputBlock ( $ blockName ) ; } else { $ this -> addOutputBlock ( $ blockName , $ method ) ; } } }
Process the 'output' attribute of a node

This is an extension that allows the output attribute to be specified on reference elements.
It also adds the ability to disable output of the node by setting the value to an empty string.

@param Mage_Core_Model_Layout_Element $node
Process the output attribute of a node