I can't figure this one out for the life of me. I have XnView on 2 Macbook's.. 1 of them works fine but the other doesn't. The issue is that I have lots of white icons in .png format with transparent backgrounds.
I'm expecting to see some background color behind the images so I can identify them - but all I get is a white block. The images display correctly in the viewer tab - so it's just the thumbnail view that's not working.
I have 'use alpha channel' option checked but that doesn't seem to do anything. I've also rebuilt the thumbnails many times so it's not that either.. and since I have another Macbook (running the same/latest version) which works fine on the same set of icons - it MUST be a setting. I just can't see if after going back and forth between them.
Any ideas? I'd really appreciate it.
Hopefully the screenshots will show this problem best
grid view:

individual image (looks fine)
https://pasteboard.co/JpoX8Yg.png
settings:
https://pasteboard.co/JpoXpxG.png