I have the following code for my combobox in a form:

Private Sub ComboBox1_DropButtonClick()
unprotectsheet
stopautocalc
Range("drwlistrng").EntireRow.Hidden = False

Sub stopautocalc()
With Application
.ScreenUpdating = False
.EnableEvents = False
.Calculation = xlCalculationManual
End With
End Sub

Sub startautocalc()
With Application
.ScreenUpdating = True
.EnableEvents = True
.Calculation = xlCalculationAutomatic
End With
End Sub

End Sub

I've tried it with both 'stopautocalc' and 'startautocalc'. The problem I
am having is the combobox isn't using the right range of cells all the time.
It seems to happen when I add rows above the range that the combobox is
supposed to pull up.

What am I doing wrong?
Thanks