GWT IE9 Dev Mode error

As pictured I see the following error when opening my page in IE9. I am on GWT 2.3.0 an开发者_如何学编程d IE9.

Is there a <set-property> tag in your gwt.xml that restricts the values of the user.agent property? This message is generated by UserAgentAsserter as a sanity-check when the runtime configuration of the module doesn't line up with the user.agent values it was compiled with.

Add

<set-property name="user.agent" value="ie9" />

to your module description (gwt.xml).