Mon problem

[mdavis6890]

Code that's causing me trouble

Ext.define('IDB.selectbox.SelectBox', {
    extend : 'Ext.form.ComboBox',
    alias : 'widget.IDB.selectbox.SelectBox',
    //clearFilterOnReset:false,
    triggerAction: 'all',
    lastQuery: '', 
    linkToCombo : undefined,
    linkFilter : function() {
        if(this.linkToCombo) {
            var linkedCombo = this.ownerCt.getComponent(this.linkToCombo.comboID);
            console.log(this.linkToCombo);
            console.log(this.linkToCombo.filterField+linkedCombo.getValue());
            this.getStore().filter([{
                property : this.linkToCombo.filterField,
                value : linkedCombo.getValue(),
                exactMatch : true
            }]);
        }
    },
    initComponent : function() {
        this.callParent(arguments);
        if(this.linkToCombo) {
            var linkedCombo = Ext.ComponentQuery.query('#'+this.linkToCombo.comboID);
            this.addManagedListener(linkedCombo, 'select', function() { //This is the problem line
                this.clearValue();
                this.fireEvent('select');
            }, this);
            this.on('expand', this.linkFilter, this);
        }
    }
}); 

Error:
item.on is not a function, ext-debug-all.js (line 5613):

// Within the Ext.util.Observable section:
5604 else {
5605    managedListeners.push({
5606       item: item,
5607       ename: ename,
5608       fn: fn,
5609       scope: scope,
5610       options: options
5611    });
5612
5613    item.on(ename, fn, scope, options);// Here's where the app breaks.
5614 }