Tag Property Lost During Drag And Drop

If I fetch the dragged ReportRecords from the clipboard the contents of the Tag Property is lost. I use the following C# code during the DragDrop event of a TreeView component:

public ReportRecords GetDraggedRecords(DragEventArgs e) {
    MemoryStream stream = e.Data.GetData(clipboardName) as MemoryStream;
    if (stream != null) {
        return report.CreateRecordsFromDropArray(stream.ToArray());
    }
    return null;
}

I also tried to handle the ReportControl's BeginDrag event and examine what will be pushed onto the clipboard, but there the Tag Property is still set. The Tag would contain a long value, so this should not be a serialization issue.