yes string has issues with utf-8
see this bug report
Dim t As Text = " üèö"
Dim s As String = " üèö"
Dim ti As Integer = t.IndexOf( "è" , Text.CompareCaseSensitive )
Dim si As Integer = s.IndexOf( "è" , ComparisonOptions.CaseSensitive)
Break
ti = t.IndexOf( "è" )
si = s.IndexOf( "è" , ComparisonOptions.CaseInsensitive)
Break