Mouse wheel scrolling problem

Hi all,

I have a html combo box in a grid cell. When I select the combo box and use the mouse wheel to scroll the combo box, it doesn't scroll the combo box, but it scrolls the grid. So I looked around the library and found the following.

function onmousewheel(event){
        var scrollbars = this.getTemplate("layout").getContent("scrollbars");
        var delta = scrollbars.element().offsetHeight * event.wheelDelta/480;
        scrollbars.element().scrollTop -= delta;
        event.returnValue=false;
        event.cancelBubble=true;
    }
    obj.setEvent("onmousewheel", onmousewheel);
  If I set "event.returnValue=true;", I can scroll BOTH the combo box and the grid at the SAME time. If I comment out the first three lines in the function, I can only scroll the combo box.

My question is, is there anyway to determine whether the grid or the combo box is selected from the event parameter? So that I can change the scrolling accordingly.

Thanks,
Welles