    /**
     * <p>A plugin for Field Components which creates clones of the Field for as
     * long as the user keeps filling them. Leaving the final one blank ends the repeating series.</p>
     * <p>Usage:</p>
     * <pre><code>
        {
            xtype: 'combo',
            plugins: [ Ext.ux.FieldReplicator ],
            triggerAction: 'all',
            fieldLabel: 'Select recipient',
            store: recipientStore
        }
     * </code></pre>
     */
    Ext.define('Ext.ux.FieldReplicator', {
        singleton: true,

        init: function(field) {
            // Assign the field an id grouping it with fields cloned from it. If it already
            // has an id that means it is itself a clone.
            if (!field.replicatorId) {
                field.replicatorId = Ext.id();
            }

            field.on('blur', this.onBlur, this);
        },

        onBlur: function(field) {
            var ownerCt = field.ownerCt,
                replicatorId = field.replicatorId,
                isEmpty = Ext.isEmpty(field.getRawValue()),
                siblings = ownerCt.query('[replicatorId=' + replicatorId + ']'),
                isLastInGroup = siblings[siblings.length - 1] === field,
                clone, idx;

            // If a field before the final one was blanked out, remove it
            if (isEmpty && !isLastInGroup) {
                Ext.Function.defer(field.destroy, 10, field); //delay to allow tab key to move focus first
            }
            // If the field is the last in the list and has a value, add a cloned field after it
            else if(!isEmpty && isLastInGroup) {
                if (field.onReplicate) {
                    field.onReplicate();
                }
                clone = field.cloneConfig({replicatorId: replicatorId});
                idx = ownerCt.items.indexOf(field);
                ownerCt.add(idx + 1, clone);
            }
        }

    });