Mostly this '99999' occurs when there are mixed results - if some lines in the range are hidden and some are not. But this is a strange behavior, might be a bug in Office.
If that is the case then you need to have some workaround like this
Sub asasa()
Dim bkmk As Bookmark
Dim line1 As Line
If bkmk.Name = "Grow" Then
If bkmk.Range.Font.Hidden = True Then
bkmk.Range.Font.Hidden = False
ElseIf bkmk.Range.Font.Hidden = True Then
bkmk.Range.Font.Hidden = True
Else
For Each p1 In bkmk.Range.Paragraphs
If p1.Range.Font.Hidden = True Then
p1.Range.Font.Hidden = False
End If
Next p1
End If
End If
End Sub
Cheers
Shasur
http://www.vbadud.blogspot.com