Liebniz and Newton invented the calculus at roughly the same time.
Alexander Graham Bell and Elisha Gray both invented the telephone at the same time, and filed with the patent office a few hours apart.
While it takes smart and insightful people to make these things happen, inventions are also the product of their time, and of other trends that are more or less well-known. Often the invention is a matter of recombining existing technologies in a novel way.
This created a stir on Mac sites, with some claiming it’s a ripoff, some suggesting that the gracious thing for Apple to do would at least be to compensate the Konfab people for pulling the rug out from underneath them, and others pointing out that in fact, there was plenty of prior art to Konfabulator. John Gruber, astute as usual, pointed out that Apple in fact is not ripping off much of anything.
Ideas like skinning, making scripting more accessible to more people, using standard markup languages to generate interfaces, etc, are ideas whose times have all come in the computing world. Lightbulbs lit up over lot of people’s heads, and they combined these ideas in similar ways. Konfabulator clearly beat Dashboard to market (though I find the product all-but unusable), but it is original only in the sense that its creators had the idea on their own (if in fact that is so), not in the sense that its creators are the only ones to have the idea.