I've checked with the RadFormDecorator developers and they confirmed that the problem has been investigated, but is in fact Google Chrome issue present in their issue tracking system: http://code.google.com/p/chromium/issues/detail?id=13170
The workaround we can offer for the time being is to disable Selects from being decorated i.e.:
<telerik:RadFormDecorator ID="RadFormDecorator1" runat="server" DecoratedControls="All"
This would disallow the select elements from being decorated under all browsers. If you want to limit the "damage", you can make a browser check in code behind and set this property only when the browser is Chrome.
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