In the current version of RadControls a visibility property of Series in RadHtmlChart is not exposed. However, this idea has already been logged in our feedback portal here
, so that you can monitor, comment or vote on it. If it gets enough votes and approval from our management you can expect it in a future release.
For the time being you can raise the priority of this item by voting on it.
All the best,
the Telerik team
If you want to get updates on new releases, tips and tricks and sneak peeks at our product labs directly from the developers working on the RadControls for ASP.NET AJAX, subscribe to their blog feed