Test this page in different browsers. Seems than in this particular case Firefox 1.5 doesn't get clear:left on the DL elements.
Update: Ok. Clearing floats inside FIELDSET doesn't work in Firefox 1.5. This bug was known before Firefox 1.5 release. They just left it in a hurry because:
Even though it is a regression, the impact is minor we are very close to lockdown for rc2 so it looks like it is not going to make it.
I hate regressions in CSS! :furious:
