This is correct for the horizontal collection views as there is no vertical scrollbar there and the horizontal one is usually "scrolled" using the Prev/Next buttons on the mouse. I'm not sure if it possible to change that reliably.

There's no such thing as a "prev button" on my mouse.

Wouter, what do you mean with "Scrollwheel on image list doesn't work"? Could you be more specific?

There is a horizontal scrollbar, so that made me believe using my scrollwheel should move the view to the left/right (scrolling the horizontal scrollbar), however this doesn't work.

(Oh, and let me add I do *not* mean that the currently shown image should be changed on a scrollwheel event, see bug #331645 for more information.)

There's also a ubuntu bug about this 
https://bugs.launchpad.net/ubuntu/+source/eog/+bug/126502

Basically it boils down to handling scrollwheel events and shifting sideways.

The "Right Thing To Do" from a user point of view, is to place the mouse over the scrollbar and use the scroll wheel there. That's the way you scroll in horizontal scrollbars with the mouse.

I would like to hear about other applications shifting sideways in the way you suggest. I understand it's easy to implement but I have my doubts about interaction consistency (scroll wheel has always been up-down and not left-right, if you know what I mean).

I do understand you objections, but since the horizontal image view has no vertical scrolling BY DEFINITION, we shouldn't make it hard for users to scroll a bit further. The image view is one-dimensional (horizontal), so we should just be a bit smarter.

I understand Claudio's objections but I agree with Wouter. Using scroll wheel for scrolling through the horizontal image list is the "smart" aproach. Done.

2007-09-04  Lucas Rocha  <lucasr@gnome.org>

        * src/eog-thumb-nav.c (eog_thumb_nav_scroll_event,
        eog_thumb_nav_init): use the mouse wheel to scroll through the image
        list only in case it's in one row mode. Fixes bug #427046.