I need help finding out the differences between Coolite 0.8 textbox trapping enter key and 3.2.1

v .08 Coolite code works:
<ext:TextField ID="SearchStringField" runat="server" EnableKeyEvents="true">
  <AjaxEvents>
    <KeyPress Before="var e = params[1]; var isEnter = e.getKey() == e.ENTER; if(isEnter){e.preventDefault();} return isEnter;"
      OnEvent="SearchString">
      <EventMask ShowMask="true" Target="CustomTarget" CustomTarget="#{gpFindStudent}" />
    </KeyPress>
  </AjaxEvents>
</ext:TextField>
Ext 3.2.1 I can't get anything to trap the enter key press