I imagine that mouse wheel events would be ignored unless the Component was focused and the mouse was over the Component.
Spinner - Equivalent to an UP/DOWN arrow key press when 'circular' property is true
Slider - Equivalent to an UP/DOWN/LEFT/RIGHT arrow key press
ListButton - Equivalent to an UP/DOWN arrow key press
CalendarButton - No current UP/DOWN/LEFT/RIGHT arrow key press functionality to change date by a single day, but would be equivalent to this. Support for these key presses could be added at the same time.