onChange/onBlur for AW.UI.Combo

Hi,
I want to set a simple onchange event to a combo box, but I cannot get it to work. Of the event handlers below, onclick and onmouseup show alerts, but doing so obstructs the behavior of the popup. Any help is greatly appreciated. Thanks.
(Using 2.0b3)

var obj = new AW.UI.Combo;
// unimportant: set a bunch of properties here...

obj.setEvent("onblur", function(event){alert("blur");});
obj.setEvent("onchange", function(event){alert("change");});
//obj.setEvent("onclick", function(event){alert("click");});
//obj.setEvent("onmouseup", function(event){alert("mouseup");});