With the official Windows 8 development samples being updated to Windows 8.1, I was running through several samples reading some code and checking for changes. Today I still had ‘break on all thrown CLR exceptions’ checked from my debug session earlier on. While running the Application Settings sample I noticed a FormatException being thrown after hitting the settings charm.
A first chance exception of type 'System.FormatException' occurred in mscorlib.dll
Additional information: Guid should contain 32 digits with 4 dashes (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx).
It seems like the OS is trying to parse the Id field of SettingsCommand to a Guid, although the parameter is of the type object. Luckily the exception is handled, so using a string as in the sample does work and your settings are shown at runtime.