I was looking at some reports where people were complaining about the whitespace on dropdowns of the Special:Delete page, when using Firefox (not Chrome or Safari, IE unknown).
I notice that it seems that these do not use the full styling for OOUI dropdowns. Possibly they are not being infused or something ?
I do agree that the styling of the native option element looks weird this way.
FF dropdown of Vector
FF dropdown of Monobook
'normal' OOUI DropdownInputWidget
The styling causing this large whitespace in the native dropdowns is the 0.5em padding of this rule:
.oo-ui-dropdownInputWidget option { font-size: inherit; font-family: inherit; height: 1.5em; padding: 0.5em 1em; }
See also: https://en.wikipedia.org/wiki/Wikipedia:Village_pump_(technical)#Drop_Down_Box