The source code

    Ext.ns('Ext.ux.form');

    Ext.ux.form.SearchField = Ext.extend(Ext.form.TwinTriggerField, {
        initComponent : function(){
            Ext.ux.form.SearchField.superclass.initComponent.call(this);
            this.on('specialkey', function(f, e){
                if(e.getKey() == e.ENTER){
                    this.onTrigger2Click();
                }
            }, this);
        },

        validationEvent:false,
        validateOnBlur:false,
        trigger1Class:'x-form-clear-trigger',
        trigger2Class:'x-form-search-trigger',
        hideTrigger1:true,
        width:180,
        hasSearch : false,
        paramName : 'query',

        onTrigger1Click : function(){
            if(this.hasSearch){
                this.el.dom.value = '';
                var o = {start: 0};
                this.store.baseParams = this.store.baseParams || {};
                this.store.baseParams[this.paramName] = '';
                this.store.reload({params:o});
                this.triggers[0].hide();
                this.hasSearch = false;
            }
        },

        onTrigger2Click : function(){
            var v = this.getRawValue();
            if(v.length < 1){
                this.onTrigger1Click();
                return;
            }
            var o = {start: 0};
            this.store.baseParams = this.store.baseParams || {};
            this.store.baseParams[this.paramName] = v;
            this.store.reload({params:o});
            this.hasSearch = true;
            this.triggers[0].show();
        }
    });