Exception in ActiproSoftware.Text.Wpf

Hi,

I have a list of some views, each containing a syntaxeditor.

When switching between the views of the list, the editor is initialised with a new language and text and some new lexical patterns to verify.

Now we get an exception - not binded to a special item, just when switching to ione or another:

NullReferenceException

Object reference not set to an instance of an object.

at ActiproSoftware.Text.Lexing.Implementation.DynamicLexicalState.#EJ(ITextBufferReader reader)

at ActiproSoftware.Text.Lexing.Implementation.DynamicLexer.GetNextToken(ITextBufferReader reader, ILexicalState lexicalState)

at ActiproSoftware.Text.Lexing.Implementation.MergableLexerCoordinator.GetNextToken()

at ActiproSoftware.Text.Parsing.LLParser.Implementation.MergableTokenReader.GetNextToken()

at Gradient.WPF.Actipro.Controls.SyntaxEditor.MengenEditor.MengeTokenReader.GetNextToken()

protected override IToken GetNextToken()
{
	// Call the base method
	IToken token = base.GetNextToken();
	// Loop to skip over tokens that are insignificant to the parser
	while (!this.IsAtEnd)
	{
		switch (token.Id)
		{
			case MengeTokenId.Whitespace:
				// Skip
				token = base.GetNextToken();
				break;
			default:
				return token;
		}
	}
	return token;
}

 and the step before that could be

either

at ActiproSoftware.Text.Parsing.LLParser.Implementation.TokenReaderBase.GetLookAheadToken(Int32 count)

or

at ActiproSoftware.Text.Parsing.LLParser.Implementation.TokenReaderBase.Advance()

Have you any idea, which object in the ActiproSoftware.Text.Lexing.Implementation.DynamicLexicalState.#EJ(ITextBufferReader reader) could be null?

Thanks!