Hi Alex,

Thank you for reporting this issue!  I've made the report public, as other users might encounter the same behavior.

This NullReferenceException that appears during debugging is expected behavior and does not represent an actual problem in your application.

Why This Occurs

Visual Studio stops at a NullReferenceException in the GetAppSetting() method when debugging with the "Break when this exception type is thrown" option enabled.

This happens because:

• The code attempts to access page.Site, which is null during runtime (this is normal behavior)
• page.Site is only intended for design-time scenarios (Visual Studio designer)
• The exception is properly handled by a try-catch block and does not affect functionality

Solutions

You can safely:

1. Press F5 (Continue) in the debugger - your application will work normally
2. Disable "Break on NullReferenceException" for Telerik.Web.dll:
   • Navigate to Debug → Windows → Exception Settings
   • Find System.NullReferenceException
   • Add Telerik.Web.dll to the exceptions list
3. (Recommended) Upgrade to the 2025 Q4 release (will be available on November 12) where this behavior will be handled internally in the source code.
   

Note: The application functions correctly regardless of this exception - it is purely a debugging behavior that can be safely ignored or suppressed.

Regards,
Rumen
Progress Telerik