Disable parameter question

Hi everyone,

Situation:

3 report parameters.  If p1 = 'N', p2 and p3 should be disabled. If p1 = 'Y' and p2 = 'N', p3 should be disabled.  I can't figure out how to disable p3 if p1='N' and p2 is disabled.

Have tried the following as possible p3 disable clauses:

-  <<p1>> = 'N' or <<p2>> = 'N'    - I get  "Expression is not valid" error

- with parentheses: )<<p1>> = 'N' or <<p2>> = 'N' )   - same error

- LEN(<<p2>>) <= 0    -doesn't disable p3

- <<p2>> not in ('N','Y')    -doesn't disable p3

Any tips?

Thanks,

Frannie