Object positioning is set to "Move but don't size with cells"

Uset this code to add checkboxes to a 25Rx4C selection of cells:

Sub SAM()
Dim c As Range
Dim lb As Shape

For Each c In Application.Selection
With ActiveWorkbook.ActiveSheet
Set lb = .Shapes.AddFormControl(xlCheckBox, c.Left + (c.Width / 3),
c.Top, 0, 12.75)
lb.TextFrame.Characters.Text = ""

lb.ControlFormat.LinkedCell = c.Address

End With
Next
End Sub

Try to insert single entire rows in the set of checkboxes. Randomly, a row
of check boxes will move with the inserted row. Next randomly, the checkboxes
will not move with the inserted row. This ain't right...