How do I make this?
 

I'm making an org chart and need each box to have a label area at the top, like the attached image (which I modified in Photoshop). In Og Pro I can take a pair of boxes and join them, but rounding the corners affects each part, not the whole grouped object. Any easy way to accomplish this?

In the Shapes stencil (in the Common folder in OmniGraffle 5) there's a special shape with two squared corners and two rounded ones (it's named Bezier). Drag it to your canvas, and duplicate and flip or rotate one of them, align and group.

That should do it nicely.

sweet, that was just what I was looking for. I feel dumb for having missed that. Thanks!

Joel, this looked interesting for me to use for wire numbers (color top part to match color codes, and number for the wire, wire type in bottom, add data for equipment) on plans.
But when I make bezier shorter, and click on it to edit the text inside it, it changes shape, adding points where I clicked and moving the line, as if I were editing the curve.
How do I stop that behavior so I can edit the text inside the shape?

Since double-clicking a shape that has points can sometimes add a point instead of editing its label, I'd suggest using the Text Tool to add text.