Mouse wheel scrolling doesn't work for DropDownList in a native window that's not the main application window in an AIR application

Steps to reproduce:
1.Create an AIR project
2.Create a custom mxml component based on spark Window component.
3.In the custom Window component add a DropDownList and give it some data (make sure to have enough data to test scrolling)
4.In the main application, on creationComplete, create a new instance of the custom window component and open it.
5.Run the application and a second window with the DropDownList should popup.
6.Click to expand the DropDownList.
7.Use mouse wheel to scroll the list.

Actual Results:
The popup is closed immediately.

Expected Results:
The list should be scrollable as normal (by dragging the thumb)

Workaround (if any):None