Conditional Formatting and Data Entry

[Guest]

I want to have a control locked except to add a row. I thought using a
condition of "equal to" null would do it (it would know it is on the "star"
row), but it didn't work. Doesd anyone have an idea as to how to keep a
control locked excpet to add a new row? Thanks.

 

[Allen Browne]

Nothing is equal to Null, not even another Null.
That kinda makes sense if you think of Null as meaning Unknown.
Explanation in issue #5 of this article:
Common Errors with Null
at:
http://allenbrowne.com/casu-12.html

In your conditional formatting, use:
Expression IsNull([MyField])
substituting the name of your actual field.