Do should have a brief fade-in/out (just a split second) when summoned.

[Matthew Pirocchi]

Right now, Do appears suddenly, and it is kind of jarring. This is a good fall-back for themes with no compositing, but the fade would be much more elegant when compositing is available. The fade time should be short enough not to effect usability--this is similar to how things work when Do is summoned in the Docky theme, and it works really well.