Updating to 2022.3.913.45 Causing Obscure Error

[Caleb]

We attempted to update our Telerik libraries from 2022.2.622.45 to 2022.3.913.45

This caused:

System.Web.HttpException (0x80004005): This is an invalid webresource request.
   at System.Web.Handlers.AssemblyResourceLoader.System.Web.IHttpHandler.ProcessRequest(HttpContext context)
   at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step)
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

Thru trial and error we were able to discover that this is caused by using RenderMode="Lightweight" on specifically RadComboBox. It causes no issue elsewhere. This option continues to be available thru autocomplete on in the aspx file as if it's valid.

We were also able to successfully set a RadComboBox to Lightweight in another empty project on this version for testing purposes.

Any idea what steps can be taken to mitigate this?

To have such a random, valid setting cause the site to break only to be given an obscure error with no information pointing to what's wrong makes me concerned of what else might be broken that we haven't noticed.

This pertains to the Telerik.Web.UI dll.

[Rumen]

Hi Caleb,

The problem is very likely caused by the following regression (logged with the highest priority):

RadComboBox Bootstrap Lightweight skin not loading in version 2022.3.913.

Please try the workarounds provided and let me know the result!