ListGrid Events are not working.. Please help...

I am using the SmartGWT 2.3 LGPL and my issue is for all browser version(s). Infact i am using only ListGrid from SmartGWT. I have a container of GWT with ListGrid as a child widget in it. I am unable to catch any event of ListGrid. for example

listgrid.addDoubleClickHandler(new DoubleClickHandler() {
@Override
public void onDoubleClick(DoubleClickEvent event) {
SC.say(“Hello World”);
}
});
listgrid.addCellDoubleClickHandler(new CellDoubleClickHandler() {

@Override
public void onCellDoubleClick(CellDoubleClickEvent event) {
			SC.say("Hello World");
			
		}
	});

listgrid.addRecordDoubleClickHandler(new RecordDoubleClickHandler() {

@Override
public void onRecordDoubleClick(RecordDoubleClickEvent event) {
			SC.say("Hello World");
		}
	});

So how to catch events of listGrid? Please help me…