Initial selection without bookmarks

[#1]

Hi everybody,

I have a column in my table that contains dates values: some rows are full and other are empty. I would like to have only the null rows selected when opening the app and I would like to remove that filter later to get all the values, null and not null.

I'm using the bi-era.com-listbox extension, but I can only have or null values either not null values, but not the whole set of values.

What should I do to get that?

Thanks in advance !