Error "The specified language can not be found." After importing a new config

Hello All,

I'm having an issue where I load an external config and then try to switch to a Known Language, I get the following error “The specified language cannot be found."

 I load an external config using:

         SnippetEditControl.BackgroundColor = New

        Syncfusion.Drawing.BrushInfo(ColorTranslator.FromHtml("#ffffff"))

        SnippetEditControl.Style = EditControlStyle.Default

        SnippetEditControl.Configurator.Open(DefaultThemeConfig)

        SnippetEditControl.ApplyConfiguration("C#")

        SnippetEditControl.SelectionTextColor = ColorTranslator.FromHtml("#bfdfff")

 This works Fine 

Later, when I try load a ‘KnownLanguages’ of 'Text' I get the error

             Select Case SelectedLanguage

                Case "Text"

                    SnippetEditControl.ApplyConfiguration(KnownLanguages.Text)

                    ........

            End Select

It seems the 'Configurator' forgets the 'KnownLanguages'. How do I bring these back?

Thanks

Andy