NextGEN Gallery – manage gallery

Under the Screen Options, I have selected all the six options including the ID, Thumbnail, Filename, Alt & Title Text / Description, Tags (comma separated list), exclude. All these six column headings are displayed as expected. But under the Filename heading, the creation dates are displayed instead of the filenames. The system seems to recognize the filename field because if I change the sorting order to filename, it will display according to filename order.