Filters are incredibly common when doing analysis. It's important to know how to interpret a filter and know when a filter is applied to a table.
The table below has a filter applied, with NaN in many of the cells not included in the filter. NaN means Not a Number; in this instance, the females have a sample size of zero after applying the filter so percentages cannot be computed. However, zeros do appear in the column for males as the total sample for men is still greater than zero. Note that the proportion of the sample filtered is shown as filtered out at the bottom right of the screen.