I believe I've discovered a bug in Safari/WebKit, but I believe the actual CSS spec is vague on the correct behavior so one could argue it's not a bug. However, Safari v3.0x (on both Windows and the Mac) does behave differently than other comparable browsers (IE7/8, FF2/3.)
The problem is when you use the :hover psuedo class in conjection with
adjacent sibling selector. In the example below, the following CSS class
is defined: ul > li:hover + li. This is designed to
change the border of the next list item element.
In Safari 3, the border is changed on mouseover, but it is never reset when the mouseout event occurs. In IE7, IE8, FF2 and FF3 the element's state is restored to it's original non-hover state. This certainly is the behavior I was expecting.
To see it action, move the mouse from the bottom of the list to top. You'll see the sibling element's style is never reverted back to white. You won't notice the behavior if you move the mouse from top to bottom, since the element will be correctly reset when you mouse over the next sibling item.