Case Insensitive Dictionary not working

I have spend a couple of hours trying to figure out why my generic Dictionary(Of String, String) is not ignoring case.

Here is my code:

Dim test As New System.Collections.Generic.Dictionary(Of String, String)(System.StringComparison.OrdinalIgnoreCase)
test.Add("FROG", "1")
Console.WriteLine(test.ContainsKey("frog"))

The console shows "False" every time. It should be showing "True".

If I use:

Console.WriteLine(test."frog")) 

I get a KeyNotFoundException.

It seems as if the Comparer parameter is being completely ignored.

What is going on?