cannot toggle between spectra using the "Back" and "Next" buttons.

[ywis]

Hi I loaded a couple of spectra in the input file. However, when doing the eye check, I cannot toggle between the spectra indicated from the input file. With the "Back" and "Next" buttons, the template do vary, however, the red curve is always the last spectrum in the input file. I was wondering if anyone can help with this issue. Thanks!