I have a question about when (if at all?) to include an action button to trigger the selecting of an item in a drop-down list for these 3 scenarios:
Scenario 1 - I have ONE drop-down list that is used to filter a list of documents shown below it (e.g. it filters the document type). Should this drop-down list have a 'Filter' action button next to it which triggers the filtering? Or should the filtering happen automatically when the user selects an item from the drop-down list?
Scenario 2 - I have have TWO drop-down lists that both act as filters to a single list of document (e.g. one filters on document type, the other on year of publishing). Should there be an action button to trigger the filtering or should it happen automatically when the user selects an item in either drop-down?
Scenario 3 - I have a drop-down list (e.g. country selector) that a user can select to navigate to a separate page for that country. Should there be a 'Go' action button that triggers the navigating or should it happen automatically when the user selects an item from the drop-down list?