I was just looking at an extremely flickering waterfall picture of a (already calibrated) CFL spectrum. I was wondering if the flickering only affected intensities or wavelengths, too. So I used the "SET NEW CROSS SECTION" button to use a different line number of the picture. As soon as I hit "APPLY" the spectrum lost its calibration and went back to "uncalibrated pixels". Do you have any idea why? Do I have to re-calibrate every time I use a different cross-section?