需要为CSV文件保存两次吗

After I edit the existed CSV file, click save will prompt a message dialog "some feature in your workbook might be lost if you save it as CSV (Comma delimited)". Then I click "Save". After that when I click "Close" to close the CSV, prompt message dialog again "Want to save your changes to 'sample.csv' ". Why I have to save twice? How to solve it? ThanksAfter I edit the existed CSV file, click save w