[code]
String rts,STR[]={"Reset","Clear","level1","level2","level3"};
p.add(cb=new Choice());
for(int i=2;i cb.addItem(STR[i]);
[/code]

The above code add selection list .
If you remove the above code. It will produce error at the following code
level=cb.getSelectedIndex();
because cb is not exist any more.
[code]
public void reset(boolean status){
level=cb.getSelectedIndex();
clear(status);
running=false;
m.stop();
s.stop();
}
[/code]