RadControls for ASP.NET AJAX support the browser versions released before the current version was released. So if you are using the latest version, which is Q1 2012, and new browser version comes in two months, it is possible to experience some issues, though it rarely happens. But in any case, soon after the browser new version release, the next version of RadControls for ASP.NET AJAX will come with the issue addressed.
All the best,
the Telerik team
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