When non-selectable options appear due to the applied filters, i.e. items with no respondents because of the filtering, the items can be removed (hidden) from the list or they can display with a greyed out, disabled style. Here we see two examples. The Country list contains Germany and US but the only US is selected so all German cities are no longer selectable. To the left, you see that the German cities are disabled and on the right side, you see that the German cities are hidden.
In case of disabling the non-selectable options, you can also choose if the disabled options will be moved to the bottom of the filter list or if they should keep the original position. Here we see the difference between the two sorting options that can be used. Either the current sort order is kept (the example to the left) or all the disabled options are moved to the bottom of the list (the example to the right).