MessageBox with question using %MsgStyle_OKCancel makes my jsonarray empty ?!

Hi,

I have some strange behaviour using MessageBox with a question using %MsgStyle_OKCancel; it seems that it makes my jsonarray empty?

Does anyone has a idea what is going wrong?

Kind regards, Bart

Local JsonArray &jArray;
Local number &Answer, &length_before_question, &length_after_question;

&jArray = CreateJsonArray();
&jArray.AddElement("Name");
&jArray.AddElement("Name2");

&length_before_question = &jArray.Length();

&Answer = MessageBox(%MsgStyle_OKCancel, "", 0, 0, "Question?");
If &Answer = %MsgResult_OK Then
/* ToCode /
Else
/ ToCode */
End-If;

&length_after_question = &jArray.Length();

Warning "&length_before_question: " | &length_before_question | " - &length_after_question: " | &length_after_question;