When using an EM based framework (CoffeeGrinder DDE or CoffeeGrinder MFE) I see px based measurements in the size area for breakpoints. I thought that I should see EM based widths with those frameworks.
Is it me, or am I missing something here?

We automatically convert to EM's on the fly for the CoffeeGrinder DDE and CoffeeGrinder MFE . You will still see the references to PX. Basically we show it in PX because that is a measurement that people are familiar with.

Gotcha! Now that makes sense,it was not my mind after all.

I grew up in the printing industry, so using EM's as a measurement is something that I do understand (as I sit here looking at my ruler with points, picas, agate, and em's on it!)