I don't think that the "Highlight All" option should be a button. Since it's a yes/no option, it should be a checkbox. If I see a button that says "Highlight all", I probably wouldn't interpret it as an option, but rather a submit button that also highlights everything, with the "OK" button either not doing any highlighting (first thought) or just highlighting the first occurrence (more logical second thought). So I'd click it, and it'd toggle, and I'd go "Oh...um...okay then." Probably wouldn't be enough to confuse me, but possibly enough to throw Aunt Tillie off, who has enough widgets to try and understand without throwing another on there.
I can kind of see where you're coming from by the "too different" line, as all the other options affect input, and this one affects output, but don't agree that this distinction warrants such a drastic difference in the widgets. I would just leave it as a checkbox, or maybe put it in the dropdown with the other options. 126.96.36.199 08:28, 25 September 2008 (CEST)