Exception in help command

[dtv42]

When using a command loop calling help with an unknown command results in an System.NullReferenceException in Future.cs

Object reference not set to an instance of an object.
at NClap.Metadata.CommandGroup`1.get_Selection()

The minimal Program to show this behaviour is:

var loop = new Loop(typeof(CommandType));
loop.Execute();

public partial class Program
{
enum CommandType
{
[HelpCommand]
Help,

    [Command(typeof(ExitCommand))]
    Exit
}

}

Typing 'help exit' works as expected, typing 'help xxx' crashes.