I have a query based on relationships. After running the
query, I like to additionally use Filter By Form. When I
click on any field, it gives me 2 options (Is Null and Is
Not Null)instead of giving me a list of items relating to
that field field.

At present, I type in the values into the Filter by form
field manually and it seems to work ok. However, I would
like to see the values automatically if possible

Any reasons as to why this could happen and is there a
solution?.