When creating multi-series line charts - null values

Hi, when I am creating a multi-series line chart, I am grouping on the values on a column, and I have some values in there that are nulls, and I would like to filter them out, but the drop down is not able to let me do so, it works ok on values that are not null. Is this a bug?

Thank you

Have you tried using the Not Empty filter setting?

ah that is great. I have another question, can I do the same w/ sql parameters?