A note on Xfce's portability:

"All but one of those screenshots were taken on machines running OpenBSD -current, a good proof that Xfce is still portable and friendly to all Unix systems."

It'd be interesting to know which of those screenshots is the one not taken on OpenBSD-CURRENT.

I guess it is the Parole media player one, due to lack of decoders on OpenBSD. The lack of decoders is purely my speculation, so it's likely wrong.