At the moment the numeric and date filters keep the filter button visible even on narrow columns. This must be implemented for the string filter as well - it has a set width at the moment.

The "clear filter" button must always be visible as well (when there is a filter applied, of course).

Ideally, the filter elements will also have a common container with an accessible class so, for example, you can set its max-width to 50% or 100px to match desired UI easily without hacking through several different layouts and selectors.