Found on DataGrid and then verified on List as well.
When the list control specified a lockedRowCount that is
greater than 0 (for DataGrid, this is almost all the time since
there is a header row), if you do pagescroll, everything seem OK,
but if you do linescroll or mousewheel scroll (especially when you
do dragging on the scroll bar quickly), then the first row of the
content and the header row will appear to be buggy (e.g. showing
incorrect row data. anybody else seen similar issue?
public var selectedItem:Object;