Animated webp - garbled appearance when animation for multipage files are diasbled

[Sprintdriver]

When manually scrolling through the frames in an animated webp page using Next/Previous page buttons, only the first opened image looks like intended. All following frames look garbled (i.e. probably XnView simply view one frame at a time with masking, disregarding previous frame instead of adding on top of previous).

The behaviour is the same for the following version combos of XnView and OS:

• Windows 10, XnView 1.7.1
• Linux Fedora (Cinnamon spin), XnView 1.6.2 (Flatpak)

[xnview]

what do you have for second frame?

[Sprintdriver]

The webp file consist of 8 frames.

The second frame - if rendered properly should look like this:

expected appearance of frame 2

[xnview]

what do you have in Xn?

[Sprintdriver]

Ah, yes - here is how the second frame actually looks on screen

second frame as shown on screen

[xnview]

the file is opened from browser?

[Sprintdriver]

the file is opened from browser?

Firefox

Frame 2 as shown in Firefox

Brave

Frame 2 as shown in Brave

So in both Firefox and Brave, the webp frames appear normally.

[user0]

from Browser tab of XnViewMP

I can't reproduce this issue on a clean unzipped 171, no matter how the file is opened.

[Sprintdriver]

from Browser tab of XnViewMP

Ah, of course, my mistake

XnView 1.6.2 viewing frame 2 in animated webp in browsing mode

Here, I've manually shifted to frame 2 by right click on image canvas and "Navigate to --> Next page"

[user0]

Your file is fine, it's just optimized - 1st frame contains the full image, other frames only contain the changes.
to reproduce:
1. check "Disable GIF/JIF/APNG/ANI animation" (Settings > View > Misc)
2. navigate frames


However, there is an issue in Browser
to reproduce:
0. have clean unzipped version
☐ Disable GIF/JIF/APNG/ANI animation
1. have folder with any animated image and subfolder
2. select image in Browser mode
3. do 'Previous/Next/First/Last page' command (right click on image>Navigate to OR View>Preview>Page OR via custom shortcut)
4. select subfolder
preview turns blank, but image is still cached?
5. repeat step 3
preview will scroll file frames

[aomaoyyw]

实际上，这个bug在1.7.1版本中还不存在，言下之意，这个webp文件能在我的1.7.1版本中正常显示。但是随着我升级到1.7.2之后，我也遇到了相同的问题，所以才来论坛里寻求帮助
Actually, this bug does not exist in version 1.7.1, which means that this webp file can be displayed normally in my version 1.7.1. But after I upgraded to 1.7.2, I also encountered the same problem, so I came to the forum to seek help
——Translated by Google

[xnview]

实际上，这个bug在1.7.1版本中还不存在，言下之意，这个webp文件能在我的1.7.1版本中正常显示。但是随着我升级到1.7.2之后，我也遇到了相同的问题，所以才来论坛里寻求帮助
Actually, this bug does not exist in version 1.7.1, which means that this webp file can be displayed normally in my version 1.7.1. But after I upgraded to 1.7.2, I also encountered the same problem, so I came to the forum to seek help
——Translated by Google

Please post a webp file