Anyone know what this error is WARN:Log:TypeError: _9 is undefined

[gcstang]

I get this when closing Tabs on a TabSet, I've tried to troubleshoot but I just can't seem to track down what may be causing it.

GWT 2.0.3
SmartGWT 2.1

00:12:39.851 [ERROR] 08:52:28.052:MUP7:WARN:Log:TypeError: _9 is undefined
com.smartgwt.client.core.JsObject$SGWT_WARN: 08:52:28.052:MUP7:WARN:Log:TypeError: _9 is undefined
 	at sun.reflect.GeneratedConstructorAccessor30.newInstance(Unknown Source)
 	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
 	at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
 	at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:105)
 	at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71)
 	at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:157)
 	at com.google.gwt.dev.shell.BrowserChannel.reactToMessages(BrowserChannel.java:1668)
 	at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:401)
 	at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:222)
 	at java.lang.Thread.run(Thread.java:619)

[gcstang]

Anyone have a solution?

No one knows how to stop this issue?