I've had the same problem
i have a comobox with 'onSelect' options, and i want get the value of a numberbox when user select a list item.
but the numberbox may NOT ready when onSelect auto triggered during the initial loading of form data
<select id="cbxDemo" class="easyui-combobox" data-options="onSelect : function(rec) {
var val = $('#nbxDemo').numberbox('getValue');// nbxDemo numberbox NOT ready when page load, we got undefined exception
alert(val);
}">
<option value="0">N/A</option>
<option value="1">B</option>
<option value="2">C</option>
</select>
i don't want to set a flag to indicates if it is triggered by page initial or .form('loadData', data) or user select.
i'm now using try-catch to avoid undefined exception, but i think it is not a good way.