This was pointed out by James.
* Attempting to use the scroll wheel in the list of sort options in the convoy information dialogue scrolls the main dialogue rather than the list of sort options.
This means that if there is a combo box inside the tab, the tab always has the priority of mouse wheel operation. So if the tab has a scroll bar, you can't scroll the combo box with the mouse wheel.
A similar symptom is confirmed in standard.

The savegame version combo box in the advanced settings dialog is located inside a tab and cannot be scrolled with the wheel.