TodoTaggerProvider.cs

    [Export(typeof(ITaggerProvider))]
    [TagType(typeof(SquiggleTag))] // this will probably be "IErrorTag" in the next release
    [ContentType("text")]          // "text" is the base of basically all content types
    internal sealed class ToDoTaggerProvider : ITaggerProvider
    {
        // Note: the "context" arg has been removed, but is still there in Beta 1
        public ITagger<T> GetTagger<T>(ITextBuffer buffer, IEnvironment context) where T : ITag
        {
            return new ToDoTagger() as ITagger<T>;
        }
    }