Hi @musquetier,
I will try to replicate this tomorrow. The behaviour of APP should be that if multiple master flats are loaded and selected the first one should be used internally. The second one would be neglected.
I’ll test this tomorrow ;-)
The option to filter the calibration frames and lights per channel for multichannel processing would be very useful and I think I can implement it soon. I would add the option to select a channel when frames are loaded, and this channel will then be indicated in the frame column.