_NET_OPAQUE_REGION

[Cody Russell <bratsche gnome org>]

I'd also like to add one other thing to the spec for this hint.  Since it's intended to be used by the compositor as an optimization, the toolkit may only want to use rgba-by-default when it knows this hint is available in _NET_SUPPORTED.  But in some cases such as a GL compositor, it may not really be advantageous to do anything with the region, so I'd like the spec to mention that it's fine for WMs to set the hint in _NET_SUPPORTED even if they choose to ignore the region and make no attempts at optimizing with it.

Thanks,

  Cody