I think that this solve your question
Private Sub Grid1_MouseUp(Button As Integer, Shift As Integer, x As Single, y As Single)
If y < 225 Then
If ord = 1 Then
Grid1.Sort = flexSortStringAscending
ord = 2
Else
Grid1.Sort = flexSortStringDescending
ord = 1
End If
Grid1.Refresh
End If
End Sub