按填充颜色对行进行分组的宏并不起作用，我不确定原因

Sub GroupRowsByFillColor()
    Dim ws As Worksheet
    Set ws = ActiveSheet
    
    Dim lastRow As Long
    lastRow = ws.Cells(ws.Rows.Count, "A").End(xlUp).Row
    
    Dim i As Long
    Dim startRow As Long
    startRow = 2 ' 假设第一行是标题行
    
    Do While startRow <= lastRow
        If ws.Rows(startRow).Interior.Color <> ws.Rows(startRow - 1).Interior.Color Then
            If startRow > 2 Then
                ws.Outline.ShowLevels RowLevels:=0, ColumnLevels:=0
                ws.Outline.SetGrouping Row:=startRow - 1, By:xlRow, Down:=False, Up:=True
            End If
            startRow = startRow + 1
        Else
            startRow = startRow + 1
        End If
    Loop
    
    ' 最后一组
    ws.Outline.ShowLevels RowLevels:=0, ColumnLevels:=0
    ws.Outline.SetGrouping Row:=lastRow, By:xlRow, Down:=False, Up:=True
End Sub