First of all, great program! :-) 

C# allows multiple indexers with different signatures.  Doxygen appears to treat these as properties and so only generates a single entry in the property list (the first indexer encountered).  

The following code demonstrates the issue: the Properties list for IndexerExample class contains only 

>string 	this [int n] [get]
> 	An accessor keyed by integer.

The Property Documentation section however contains both sets of information.


 class IndexerExample
    {
        /// <summary>An accessor keyed by integer</summary>
        /// <param name="n">Integer key</param>
        /// <returns></returns>
        public string this[int n]
        { get { return ""; } }

        /// <summary>An accessor keyed by string</summary>
        /// <param name="s">string key</param>
        /// <returns></returns>
        public string this[string s]
        { get { return ""; } }
    }