Owner-drawn ListView constantly redraws

I've got a basic owner-drawn listview (in Details mode) set up with the following handlers:

void SinkHandlerDrawColumnHeader(Object Sender, DrawListViewColumnHeaderEventArgs E)
{
     E.DrawDefault = true;
}

void SinkHandlerDrawItem(Object Sender, DrawListViewItemEventArgs E)
{
    E.DrawDefault = true;
    TrackingMessage Data = (TrackingMessage)E.Item.Tag;
    E.Item.SubItems[0].Text = Data.Line().ToString();
    E.Item.SubItems[1].Text = Data.Message();
}

void SinkHandlerDrawSubItem(Object Sender, DrawListViewSubItemEventArgs E)
{
    E.DrawDefault = true;
}

While the above code works, the listview is constantly being redrawn whenever it's visible. Any idea why?