Try Alt+Wheel
This is what I would expect, but it doesn't do differently as I use only a wheel. Could it be somewhere in the settings of the KDE itself?
Yes, Alt+Wheel normally works. I think it's a standard shortcut in Qt apps. (Gtk apps use Shift+Wheel.)
This assumes you're not in Fit Width or Fit Page mode, of course.
Isn't drag to pan, or the minimap in the preview pane, or the cursor keys sufficient for your task?
Unfortunately, Alt+Wheel doesn't work. It does the same as Wheel only. This is how it was forever. I'm not in fit page or fit width mode, no. Never worked with older versions, nor with the latest plasma Fedora 40 KDE spin where Plasma 6. All my mice with a single wheel and do not tilt. I'm out of luck.
Alt+Wheel works for me. Plasma 5.27.5, Qt 5.15.8, Okular 22.12.3.
Is it possible you have overridden the default shortcuts, or something is interfering with them?
Do you have an unusual mouse wheel, like one that rolls freely instead of in steps, or a touchpad-simulated one?
Maybe you've discovered a Plasma 6 bug?
Many mice can scroll sideways by tilting the scroll wheel. If that's something you use often enough, maybe that's something to consider
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