Last Update: 8/1/2018
In the top panel, Available Data, of the Plot Setup dialog, you can right-click in the list of worksheets and select Auto Apply Designations. It will now be checked and the columns in the middle list will automatically have the plot designations assigned (which is read from the source worksheet).
In the middle panel of the Plot Setup dialog, click the Switch to Default Mode button . The middle list will now show the plots assigned by the column designations set in the source worksheet.