Two suggestions here:
"Render to Screen"
While designing/mutating, it can be useful to frequently check the
genome at a slightly higher resolution than the preview (like a medium-
quality 320x240). After a while it becomes pretty tiresome to have to go
to the Finder every time and double-click on the saved image file to see
the result.
"Render in Background"
An option that re-nices (or equivalently) the rendering process to a lower
priority. Currently, when I start a cpu-intensive rendering, my computer
gets bogged down. While rendering, Oxidizer does not agree so well with
my virtual desktop (CodeTek) - if I try to switch to another desktop, the
Oxidizer windows are still stuck to the current screen, making a bit of a
mess of things.