How to use UX SearchField?

I'm using a custom theme that extends the Neptune theme and I've written my own MyApp.ux.form.SearchField class based on the Custom Form Field example.

Here's my code:

Code:

Ext.define("MyApp.ux.form.SearchField", {
    extend: "Ext.form.field.Trigger",


    xtype: "myapp-searchfield",


    trigger1Cls: Ext.baseCSSPrefix + "form-clear-trigger",


    trigger2Cls: Ext.baseCSSPrefix + "form-search-trigger",


    hasSearch : false,
    paramName : "query",


    initComponent: function() {
        var me = this;


        me.callParent(arguments);
        me.on("specialkey", function(f, e){
            if (e.getKey() == e.ENTER) {
                me.onTrigger2Click();
            }
        });
    },


    afterRender: function(){
        this.callParent();
        this.triggerCell.item(0).setDisplayed(false);
    },


    onTrigger1Click : function(){
        var me = this;


        if (me.hasSearch) {
            me.setValue("");
            me.store.clearFilter();
            me.hasSearch = false;
            me.triggerCell.item(0).setDisplayed(false);
            me.updateLayout();
        }
    },


    onTrigger2Click : function(){
        var me = this,
            value = me.getValue();


        if (value.length > 0) {
            // Param name is ignored here since we use custom encoding in the proxy.
            // id is used by the Store to replace any previous filter
            me.store.filter({
                id: me.paramName,
                property: me.paramName,
                value: value
            });
            me.hasSearch = true;
            me.triggerCell.item(0).setDisplayed(true);
            me.updateLayout();
        }
    }
});

I can't figure out how to make the magnifying glass icon show up in the field like the example. I'm pretty sure I need to somehow tell my theme (or maybe even the base Neptune theme) about the new CSS classes that are required (x-form-clear-trigger and x-form-search-trigger) but I can't find any documentation that shows the required steps.



How to use UX SearchField?