How to set tool size info to pixels rather than inches?
 

When I'm drawing a box, I would like to see the measurement in pixels rather than inches. How do I change this?

I figured it out, after awhile. :)

It's in the Canvas Inspector - you can change the ruler units and that will change the units when you draw.

I must admit it isn't very intuitive, and you have to set it for each canvas. Photoshop just lets you change unit in preferences.

If you want anything as the default in OmniGraffle, create a new template with the desired settings, and make that template the default one used by the programme.