Internet Explorer (v6, and presumably older versions) fails to correctly re-draw multi-line SELECT objects with relative font-sizes when changing the page's text-size (View menu > Text Size > any other size). It maintains artifacts of the original rectangle's visual contents over top of the new rectangle. (If you can't see it, here's a screenshot).
with relative font sizes:
plain:
(The fieldset around the culprits doesn't affect the phenomenon.)
plain:
plain:
size="4":
multiple:
Documented 2004-09-24 by Rob Eberhardt, Slingshot Solutions