Please try to override the 'query' and 'enter' key handlers to let the combobox component accept the inputing value quickly.
$('...').combobox({
url: ...,
valueField: 'id',
textField: 'text',
onSelect: function(row){
console.log(row)
},
keyHandler: $.extend({}, $.fn.combobox.defaults.keyHandler, {
query: function(q){
q = $.trim(q);
var t = $(this);
var opts = t.combobox('options');
var panel = t.combobox('panel');
var data = t.data('combobox').data;
var item = $.easyui.getArrayItem(data, opts.textField, q);
if (item){
t.combobox('select', item[opts.valueField]);
}
panel.panel('close')
},
enter: function(e){
var t = $(this);
t.combobox('hidePanel');
}
})
})