[JKT]

Use the Send Feedback... item under the Help menu in OmniGraffle.

It is very disappointing that arc drawing is still absent from OmniGraffle 5.0, especially when it was requested as a feature by so many people.

You can now draw bezier lines in OmniGraffle 5 which will allow you to create an arc or arcs, but it is an awfully large amount of work for something that should be a lot easier to do - especially if you need to modify the arc at a later time.