title: Should a ComInterfaceType attribute ever not be InterfaceIsDual
body: <p>I'm implementing an IDispatch interface in managed code C#. Reading through the documentation (yes I know this is a bad idea) it says I can use <code>InterfaceIsDual</code>, <code>InterfaceIsIDispatch</code> or <code>InterfaceIsIUnknown</code> . I want my interface to be late binding so I'd choose <code>InterfaceIsIDispatch</code> .. But then some more reading shows that <code>InterfaceIsDual</code> should be the same. Will there by any functional difference between choosing the Dual and the Dispatch?</p>