Indeed, there is a browser limitation that allows only 31 stylesheets to be loaded on a page, which is described in this blog post
. When you include too many RadControls on the page, this limit is reached because each control requests a separate stylesheet and the additional styles are not loaded.
As you have already found out, the RadStyleSheetManager helps with avoiding this browser limitation because it combines the requests for the CSS stylesheets.
Feel free to contact us again if you run into more difficulties.
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