throw new IllegalStateException();
System.out.println("unablet to handle command " + cmd.getLabel() + ": nextDisplayable == null.");  return;
	public void commandAction(Command cmd, Displayable thisScreen) {		if (this.nextDisplayable == null) {			throw new IllegalStateException();		}		Displayable next = this.nextDisplayable;		this.nextDisplayable = null;		//#debug		System.out.println("Alert: setting nextDisplayable=" + next );		StyleSheet.display.setCurrent( next );	}