public ValueOrderSignature(
            string syntax,
            string description,
            ITrackingSpan trackingSpan,
            ISignatureHelpSession session)
        {

            _propertyName = "Syntax";
            _syntax = syntax ?? string.Empty;
            _description = description;
            _trackingSpan = trackingSpan;

            _content = string.Format(CultureInfo.InvariantCulture, "{0}: {1}", _propertyName, _syntax);
            _nameParam = new CssPropertyNameParameter(this);
            _currentParam = _nameParam;

            _session = session;

            // In order to dismiss this tip at the appropriate time, I need to listen
            // to changes in the text buffer
            if (_trackingSpan != null && _session != null)
            {
                _session.Dismissed += OnSessionDismissed;
                _trackingSpan.TextBuffer.Changed += OnTextBufferChanged;
            }
        }
        public ValueOrderSignature(
            string syntax,
            string description,
            ITrackingSpan trackingSpan,
            ISignatureHelpSession session)
        {
            _propertyName = "Syntax";
            _syntax       = syntax ?? string.Empty;
            _description  = description;
            _trackingSpan = trackingSpan;

            _content      = string.Format(CultureInfo.InvariantCulture, "{0}: {1}", _propertyName, _syntax);
            _nameParam    = new CssPropertyNameParameter(this);
            _currentParam = _nameParam;

            _session = session;

            // In order to dismiss this tip at the appropriate time, I need to listen
            // to changes in the text buffer
            if (_trackingSpan != null && _session != null)
            {
                _session.Dismissed += OnSessionDismissed;
                _trackingSpan.TextBuffer.Changed += OnTextBufferChanged;
            }
        }