Google Category Filter include blanks

[moresugarmore]

I have a column I have added a Category Filter to. It all works as expected but some rows in this column are blank. The category filter by default does not create a blank option since it only makes options for actual distinct values in that column. But the user want to be able to see the rows where this column is blank. Is there a way to customize the filter category options to add a "filter by blank" value? Thank you.