What is it with wearing stoles on the OUTSIDE?

I'm constantly perplexed by pictures of deacons and priests (I don't think I've seen a bishop do it) who wear their stoles outside their dalmatics and chasubles. Where did the idea come from, and why has it stuck around?

I notice a good number of these stoles are decorated to some degree — while the chasuble or dalmatic is rather bland in decoration. Perhaps that's why? Why not restore those good old decorated chasubles and keep the stoles on the inside where they belong?

(NB: the stole is a sign of authority, the chasuble is a sign of charity... so what does it mean when a priest wears his stole over his chasuble, rather than the other way around?)

Liturgy: The Pope's new clothes

Check out the vestments designed for the Pope to wear during World Youth Day!

(H/T to Fr. Z)