Sort of obscure bug, new or old?
Bug: Get a combo, then make about 1/2 its elements disabled. Then run it, and put the mouse cursor right on the arrow of the combo and click. Then move the mouse over the dropped down elements, and use the wheel. You should be able to select any element, whether it's enabled or disabled, with a little practice, anyway.
Fix: Put NODEFAULT in the combo Mousewheel event.
The Anonymous Bureaucrat,
and frankly, quite content not to be
a member of either major US political party.