Null-Reference Exception when showing Syntaxeditor

Hello Dear

We have encountered a bug (maybe) relating to a null reference exception in the Actipro SyntaxEditor loaded with the C# language.

When this failure is approved via OK, our whole software crashes asking for sending the troubleshoot to Microsoft.

Unfortunately i can't reproduce this failure step by step, it occurs sometimes when opening/closing the Syntaxeditor many times. (Opening it, do coding, closing it, step to an other place, do coding, close it and so on)

- Used on a Windows XP Professional Machine SP2

The only Information i can send to you is the stacktrace; I did not try to dis-assemble due to obfuscation.
---> System.NullReferenceException: Object reference not set to an instance of an object.
at ActiproSoftware.SyntaxEditor.SyntaxLanguage.a(Document A_0)
at ActiproSoftware.SyntaxEditor.SyntaxLanguage.a(Document A_0, EventArgs A_1)
at ActiproSoftware.SyntaxEditor.Document.a(ISemanticParseData A_0, TextRange A_1, Boolean A_2, Object A_3)
at ActiproSoftware.SyntaxEditor.Document.ActiproSoftware.SyntaxEditor.ISemanticParseDataTarget.NotifySemanticParseComplete(SemanticParserServiceRequest request)
at ActiproSoftware.SyntaxEditor.SemanticParserService.a(SemanticParserServiceRequest A_0)
at ActiproSoftware.SyntaxEditor.SemanticParserService.c()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.runTryCode(Object userData)
at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()

Any idea what this could cause?

Thanks for your help