The up-down keys have effect on the 'active' element, which is initially the main document view, but doing something in the thumbnail sidebar transfers focus to that scrollable. It is indicated by a 1px blue outline around the scrolled area, if the action was a scroll with mouse wheel, but not in case of a click. In this state up-down keys switch pages. However, scrolling the main view with the mouse doesn't set focus back to the main view. Pressing the tab button or clicking on the document view transfers the focus back to it. This behavior is also inconsistent with the zoom combobox. That one always transfers keyboard focus to the main document view after any mouse action on it, and only gets the blue outline, when trying to scroll in a direction where no more options are available. Okular 0.14.3 in Debian Unstable, widget style is Plastique. Reproducible: Always
Do you have any suggestion for the behaviour you'd like?
I think scrolling the main document view with the mouse wheel should give it the keyboard focus. Perhaps an even better solution would be to make it consistent that the up-down keys scroll the document, and pgup-pgdown keys jump pages in all cases, but this policy might interfere with the usage of the table of contents sidebar. Hard to judge without a usability survey. Now that I've been playing with it a little more, I found that mousewheel over the thumbnail bar also steals the keyboard focus from the find popup (ctrl+f), which should be fixed similarly IMHO.
Albert, does comment #2 provide the requested information?
Kind of yes
Thank you for the bug report. As this report hasn't seen any changes in 5 years or more, we ask if you can please confirm that the issue still persists. If this bug is no longer persisting or relevant please change the status to resolved.
The current behavior (version 20.12.2) is much better than before, as the mouse wheel doesn't transfer keyboard focus between the main document and the sidebar. When the keyboard focus is on the thumbnails, the cursor and page keys work differently than when the focus is on the main document, but it's kind of expected, so it's not an issue. I think it's okay to close this bug now.