Smart Group criteria editing doesn't seem correct

I can't seem to usefully edit a smart group's criteria. Attached is a screenshot of what I see when I try. Note that the criteria themselves are correct: "Street IS NOT NULL ...AND... Do Not Mail != 1 ...AND... Contact Type - 'Individual'". But there are several problems with the editing form -

1) the first line says "operator" instead of "IS NOT NULL"

2) the second line has a couple of empty drop-down menus instead of whatever they're supposed to be

3) when I click the ">> Another search field" link, it just seems to re-load the page, with the "Edit Search Criteria" section collapsed again, and no additional search field added.