Thank you for the quick reply. With only Face Window on (no other plugins), it's still grabbing 12 px from somewhere even when the padding is set to 0 in the plugin. With Custom Menus turned on, I'm getting the same behaviour as before, no padding if the global setting is 0 and padding if there's any number in the box. I made a new project with only Book+Face Window and UI Customizer and the behaviour is also the same.