>>A user of one system I've written, who is quite quick, observed that the mousewheel on her Microsoft mouse would work in a Grid, but does not work in a drop-down combo box. How can we make the mousehweel operational in the drop-down combobox?
>
>In my expirience, the mousewheel works as long as mouse poiner has not been moved over dropdown list.

OK, just tried that - and nothing happened until I clicked, then all the scrolling inside the (undropped) combo played out... with all the form refreshes that happen in combo.valid on that form ;). If that's the behavior, I preferred when it did nothing.

And if combo is dropped, nothing happens at all, scroll all I like.

[update] Couldn't repeat the above cartoon - it seems I was just lucky with timing to have all of that happen fast and seem to be in that order.

The reason mouse wheel is unusable while mouse is over a dropped portion is that this portion behaves like a popup menu, i.e. it's selected by mouseOver, which takes precedence over anything else but the click.