Add a checkbox ftseries to conserve .h5 input file if no .h5 found in the current data directory.
if no ft_*.h5 files within the data and this option is selected, keep the "old" .h5 input file, otherwise, pop up the panel to select .h5 file.
if no ft_*.h5 files within the data and this option is selected, keep the "old" .h5 input file, otherwise, pop up the panel to select .h5 file.