Created Unassigned: Freezing first row causes scroll wheel to no longer work. [9374]

When I freeze the first row, the scroll wheel no longer works. This is because the active pane is still set to the default of TopLeft (or TopRight, not sure which). So the scroll wheel is trying to scroll the frozen row. Open XML sets the active pane to bottom left or right to keep the scroll wheel working, with code like the following:

```
WorkbookPart wbp = doc.WorkbookPart;
WorksheetPart wsp = wbp.WorksheetParts.First();
SheetViews sheetviews = wsp.Worksheet.GetFirstChild<SheetViews>();
SheetView sv = sheetviews.GetFirstChild<SheetView>();
Selection selection = sv.GetFirstChild<Selection>();
selection.Pane = PaneValues.BottomLeft;
```

Is there a way to set the active pane to BottomLeft or BottomRight in ClosedXML?

Thanks!