pasted record in locked form crashes database

i have a form with a subform and on the main form i have a toggle button that
locks the subform..
with this code
[Forms]![F_Parts_Search]![F_Parts_Browse_All].Locked = bLock
this worked fine until i found out that a record can be selected and pasted
but then because of a unique index on a control you cant move on and cant
edit the field with the unique index so youre stuck..

i cant seem to get the following code to prevent additions if that is what i
want to do?? i get a runtime error 438 "object does not support this property
or method
block is a boolean
Me![F_Parts_Browse_All].AllowEdits = not bLock
or this either
[Forms]![F_Parts_Search]![F_Parts_Browse_All].Form.AllowEdits = Not bLock

i cant use enable = block because i have a few double click fields to open
other records

any ideas would be greatly appreciated

Barry