I edit the default clock format but my clocks don't change

The checkboxes and pop-up menus in the Default Clock pane of World Clock Deluxe Preferences don't affect existing clocks: World Clock Deluxe uses the default clock format just to setup new clocks.

To apply the same format to multiple clocks:

1. Choose Pane > Clocks and open the Clocks pane.

2. Select the clocks whose format you want to edit and click the Edit button.

3. Change the selected clocks' format as needed and click OK.