XnView Software

Currently if you use the mousewheel with an unassigned modifier, it scrolls rapidly through the files just as the mousewheel would normally do unmodified.
Can I recommend it should do no action.
The reason is that if you have a modifier down it's probably because you hit the wrong key and are not intending to move through files, so for example beside the ctrl key on this keyboard is the "context menu" key, and when I intend to do a zoom using ctrl-mousewheel, without looking I hold down this context menu key, and the files zip through unexpectedly. I think this is particularly going to impact people who hop around keyboard layouts.
David

what do you have in Settings>Mouse?

I have the attached.

I imagine the problem here is that XNView needs to look more widely than shift, ctrl, alt in order to consider the wheel has no modifier (not just for this issue, but there maybe other similar ones where "no modifier" is calculated). Ideally no other key of any kind anywhere on the keyboard should be being pressed, but if that's not trivial then it may be different keyboard layouts could be considered as to what's around the shift, ctrl, alt that could be accidentally hit instead of those modifiers. In this case it is the context menu key immediately right of the ctrl key. It's an issue here because it scoots through the files. I suppose a workaround would be to make the move-file itself a modified mousewheel but I think the general issue of how not-modified is calculated needs addressing.

David

sorry but i don't understand, when you press Shift or Alt you have the same behavior like no modifier?

Ctrl, Shift, Alt basically work fine (though see my bug report on Alt)
The problem is that "no modifier" seems only to look at Ctrl, Shift, Alt to assess whether there is a modifier or not, so if e.g. you try to do Ctrl-Wheel in order to Zoom but miss the Ctrl key and hit the one beside, e.g. ContextMenu, xnview thinks the Wheel isn't modified and so carries out the not-modified act (e.g. scrolling through files) when in fact it is modified, just not with Ctrl Shift or Alt but with ContextMenu.
So I'm saying to be considered as Unmodified needs examining more than whether Ctrl, Shift, Alt are pressed, but also whether any key anywhere is pressed, though if that's difficult, a simplified examination will check the keys normally found around Ctrl, Shift, Alt, which is probably not many, because the issue arises due to missing the intended modifier key.
So for my keyboard "Unmodified" in that simplified form means that Ctrl Shift Alt AltGr ContextMenu Ç : are not pressed
David