A Chart-file (*.tee) contains all the settings in the Plot->Chart Settings for Active Plot... dialog (when no curves are plotted).
A new chart-file may be selected from the list of available files. Use the button to save the current chart file, use the button to save the current chart file with a new name and the button to delete the current chart file. If you delete a chart-file and you must get it back, you can restore it by reinstalling WinMLS.