onChange event on combo is triggered twice

Is it normal to have the onChange event for a combo being triggered twice?

I just attach the event onChange to my combo, and when the event is called I display the old and new value from the parameter, to see exactly what is going on.

This is how I attached the event to my combo:
$$(“comboNPA”).attachEvent(“onchange”, function(oldValue, newValue) {
dhx.notice(‘onChange: old=’ + oldValue + ’ newValue=’ + newValue + ’ value=’ + $$(“comboNPA”).getValue());
});

When I select an item from the list of the combo, I get 2 dhx.notice displayed.

Thanks.

I have attached the fixed libraries.
libs.zip (150 KB)