Hi developers, I have a log file for you with information about this problem. I posted this topic there, but this issue stil not solved. Error beep is played in edit fields "to" / "from" of Outlook Express. In this log file, there are some lines with error messages. Example: TypeError: not all arguments converted during string formatting I hope, that you wil have enough information for repairing this problem. Thanks in advance. Regards Matej Plch P.S: I want to thank you for creating cell editor in MS Excel. It works fine. Great job!