Unfortunately, there is no option like fixed width format. This might be a feature request. Just to remind you, the Sort feature can be used in any text files, not limited to CSV, TSV or DSV. If first x-column characters are the same across the entire document, you can still use the Sort feature for the entire document. If this is not the case, you might want to write a macro for this purpose. Please let me know if I can help you with writing such a macro. Thanks!