https://bugs.winehq.org/show_bug.cgi?id=51692
--- Comment #7 from Esme Povirk madewokherd@gmail.com --- For the Wine Mono part, it's using System.Windows.Documents (bug 50994): [0000016c:] EXCEPTION handling: System.NotImplementedException: The method or operation is not implemented. "UIThread" tid=0000016c this=037402b0 , thread handle : 03f36e60, state : not waiting at MS.Internal.Text.InternalEncoding.GetEncoding (int) [0x00001] in <80aab7a73ff941e5b7a145315a1a105b>:0 at System.Windows.Documents.RtfToXamlLexer..ctor (byte[]) [0x00024] in <80aab7a73ff941e5b7a145315a1a105b>:0 at System.Windows.Documents.RtfToXamlReader.Initialize () [0x00001] in <80aab7a73ff941e5b7a145315a1a105b>:0 at System.Windows.Documents.RtfToXamlReader..ctor (string) [0x00020] in <80aab7a73ff941e5b7a145315a1a105b>:0