My problem is that when I place :focus style for our dropdown lists like so: input, select { margin: 0; padding: 0; } select:focus { background: #FFC; } ...the dropdown with the focused selection suddenly has an extra spacing on all sides (1-2px spacing). See images below: It may seem unnoticable on the photos above but when you do a selection, the increase in padding/spacing cannot be missed. I already tried removing margin: 0, padding: 0, thinking that the :focus state might be reverting to the padded version but still the same. Has anybody encountered this problem? Only happens in Firefox.