enableMouseWheelEvents

Enable or disable mouse wheel events.
[read/write property] enableMouseWheelEvents([out, retval] VARIANT_BOOL *on) enableMouseWheelEvents([in] VARIANT_BOOL on)
This property enables or disables mouse wheel events (see MouseWheel).

Mouse wheel events are handled completely separately from mouse button and movement events - see enableMouseEvents, enableMouseBtnEvents, and enableMouseMoveEvents.

VB:
viewer.enableMouseWheelEvents = True ... Private Sub viewer_MouseWheel(distance As Long) ' by default, distance = 120 for "up" or -120 for "down" End Sub
MouseWheel
enableMouseEvents
enableMouseMoveEvents
enableMouseBtnEvents