It seems there is a bug in the way Firefox handles dropdowns.
When a dropdown (a
select in HTML) is located in a list (
dl in HTML) plus that particular list has
overflow: auto; set and is floated, the dropdown disappears when you change the selected item. So far I tested this in Firefox 1.0.4, IE 6 and Opera 8.
Only Firefox seems to be affected.
The only solution I have so far is not to set overflow and float on that list. Put one of them on a container.
Here is a sample.
Update: it seems IE on Mac doesn’t even show the dropdowns at all. (thx Peter-Paul Koch)