Debugging exception no longer working

I am developing for Windows Phone 8, and recently, not sure what I have done, the debugger no longer throw me the line number of the CS file where exception occur.

This is the only message I get (TaskHost)

Unhandled exception at 0x76C91EDB (KERNELBASE.DLL) in TaskHost.exe: 0xE0434352 (parameters: 0x80131604, 0x00000000, 0x00000000, 0x00000000, 0x70290000).

I hope someone can help me, to reconfig Visual Studio to show me the exact line number where the exception occurs.

Issue found. In project properties > Debug > UI Task

The value somehow is "Native only". I changed it back to "Managed Only" and it works. Thanks @Hans Passant for tips.