compile error can't assign to read-only property vba

Wrote a simple code to unlock the grouping function in a protected worksheet seen below

Private Sub Workbook_Open()
MsgBox ("Select Your Tab Before Entering Data"), vbInformation
Dim sht As Worksheet
For Each sht In Worksheets
    With sht
        .Protect Password:="11111", userinterfaceonly:=True
        .EnableOutlining = True
            End With
Next 'sht
End Sub

Later added additional code to edit the objects in the protected woksheet

.ProtectDrawingObjects = False

Now I get the following error: Compile error: can't assign to read-only property


Can anyone help this noobe fix this???


Moderator's Note: Don't foget to use code tags. I'll do it for now. Thanks.