Some do; some don't. Source: both of my flatmates have bought these screens; the buttons don't work on any of them (and nor do any but the DVI inputs). It's not like it really matters (after seeing these things I'm saving my pennies to grab a couple myself :)!), but the quality and functionality does differ from manufacturer to manufacturer (and from batch to batch internally - 2 of the 3 can overclock to a 120Hz refresh rate, the other can't).