Drupal Views and exposed filters - how to reset optional drop-down list filter, or allow “all” selection

Question

I have a view with a filter by country. Country is an optional CCK text field with drop-down list selection from a predefined list.

When I expose the field as an optional view search filter, I can select a country on the filter form just fine, but how can I handle no selection? I want the user to be able to "un-select" any previously selected value so that the query runs for all countries (or, to be more precise, does not constrain the results by country). I cannot add "all" as a value to the CCK field for obvious reasons. Selecting all countries in the drop-down on the search filter is not very user-friendly and causes the page to time out (there are over 200 countries in the list, and I can only imagine the resulting SQL query). Whats the best way to handle this?

I found this View Filters Reset hack which could be helpful. The desire to memorize the last selection adds another complication - when configured in the View properties, and once the (persistent) cookie is set, there is no way to get rid of the selection (short of manually deleting the cookie).

Answer 1

The answer was to check "Force Single" on the filter properties. This made <any> show up as a selection in the country filter drop-down. It kind of makes sense, because <any> in a multiple-selection list could be seen as ambiguous. Still, I can think of valid reasons why a multiple selection filter might be optional. Drupal surprises me every day.