OS: Windows 10
Contents of ZIP archives which are packed into a ZIP archive are not displayed
Effect: Browsing nested ZIP archives (i.e. archives in archives) doesn't work.
Note: From my point of view nested archives are not very common. So I'd consider severity of this bug as medium/low.
To reproduce:
1. Download the ZIP archive "ZipInZip.zip" attached to this topic and save it on a local drive. Do not unpack it.
2. Start XnView MP
3. Browse the ZIP archive by double-clicking on it. --> "Archive 1" and "Archive 2" are shown
4. Double-click on "Archive 1".
Actual behaviour (bug): No thumbnails are displayed.

Expected behaviour: Thumbnail of file "101.png" is shown.