1.91.5: "Use alpha channel" option ignored

[TheWip]

Hello,

I enabled the "Use alpha channel" option to better view images having an alpha channel - seems obvious!
However, when viewing these images in fullscreen from the browser the first shown is OK but the next ones just ignore the alpha channel!

While searching for a workaround, I find out that the "Read one image ahead" option is involved since there's no more problem when disabled.

Note: fullscreen viewing/navigation from the edition mode is OK!

[marsh]

Confirmed.