GXT 3.0.0-beta2

When I enter an invalid number in a number field, for example "3.4.5.6", instead of the the mark invalid actually getting called, it throws an exception.

Caused by: com.google.gwt.core.client.JavaScriptException: (TypeError): Object doesn't support this property or method
at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:248)
at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:136)
at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561)
at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:269)
at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91)
at com.google.gwt.dom.client.Node$.appendChild$(Node.java)
at com.sencha.gxt.widget.core.client.form.error.SideErrorHandler.markInvalid(SideErrorHandler.java:116)
at com.sencha.gxt.widget.core.client.form.Field.markInvalid(Field.java:446)
at com.sencha.gxt.widget.core.client.form.Field.markInvalid(Field.java:253)
at com.sencha.gxt.widget.core.client.form.Field.forceInvalid(Field.java:128)
at com.sencha.gxt.widget.core.client.form.NumberField.onCellParseError(NumberField.java:86)
at com.sencha.gxt.widget.core.client.form.ValueBaseField$1.onParseError(ValueBaseField.java:44)
at com.sencha.gxt.widget.core.client.event.ParseErrorEvent.dispatch(ParseErrorEvent.java:85)
at com.sencha.gxt.widget.core.client.event.ParseErrorEvent.dispatch(ParseErrorEvent.java:1)
at com.google.gwt.event.shared.GwtEvent.dispatch(GwtEvent.java:1)
at com.google.web.bindery.event.shared.EventBus.dispatchEvent(EventBus.java:40)
at com.google.web.bindery.event.shared.SimpleEventBus.doFire(SimpleEventBus.java:193)
at com.google.web.bindery.event.shared.SimpleEventBus.fireEvent(SimpleEventBus.java:88)
at com.google.gwt.event.shared.HandlerManager.fireEvent(HandlerManager.java:127)
at com.sencha.gxt.cell.core.client.AbstractEventInputCell.fireEvent(AbstractEventInputCell.java:41)
at com.sencha.gxt.cell.core.client.form.TriggerFieldCell.finishEditing(TriggerFieldCell.java:205)
at com.sencha.gxt.widget.core.client.form.Field.finishEditing(Field.java:205)
at com.sencha.gxt.widget.core.client.grid.editing.GridInlineEditing.onEnter(GridInlineEditing.java:283)