When the tabs don't fit into the vertical space of the sidebar, a scrollbar appears and the mouse wheel can no longer be used to switch tabs. Instead, it causes normal vertical scrolling. Desired behavior is normal scrolling only when the mouse cursor is on the scrollbar, and tab switching when the mouse cursor is located over the tabs.
Confirmed on Falkon 3.1.0.
Looks like a feature since there does not seem to be implemented mechanism to autoscroll the sidebar to follow the current tab. This has to be doen before this feature can be changed. Because it would not be nice if you changed tabs with mouse wheel and at the same time you could not see anything.
A possibly relevant merge request was started @ https://invent.kde.org/network/falkon/-/merge_requests/80
Git commit ccce0818ccbc18ea402cb88794999a265142ddb3 by Juraj Oravec. Committed on 18/08/2024 at 18:36. Pushed by jurajo into branch 'master'. VerticalTabs: Fix tab switching with mouse wheel Respect the "Always switch between tabs with mouse wheel" option. FIXED-IN: 24.12.0 Signed-off-by: Juraj Oravec <jurajoravec@mailo.com> M +13 -0 src/plugins/VerticalTabs/tabtreeview.cpp M +2 -1 src/plugins/VerticalTabs/verticaltabswidget.cpp https://invent.kde.org/network/falkon/-/commit/ccce0818ccbc18ea402cb88794999a265142ddb3