I do not think this is an issue with FreeCommander.
I am also experiencing similar behavior in Windows Explorer.
I would think this is an issue with Windows.
Best Regards
FreeCommander XE 2025 Build 937 64-bit donor
Windows 11 Pro 64-bit Version 25H2 Build 26200.7019
I have been experiencing similar issues intermittently. Sort order is not respected accordingly. sometimes I have files listed twice and sometimes i.e. Download, the file is not shown in the tab.
FreeCommander XE 2025 Build 937 64-bit donor Windows 11 Pro 64-bit Version 25H2 Build ...
After testing with various settings I conclude that the mouse wheel function will only work when the viewer panel is in focus, i.e. click in the viewer to set it in focus or activate the setting of the viewer to automatically set it in focus when the file is opened.