How is this a Paint.NET related development question ... ?
I downloaded the paint.net source the other day and spent some time hunting through the source to see if I could find somewhere this had been done. I couldn't find any other good resources on the internet, so I didn't figure it'd hurt to ask here. So, I guess in answer to your question, it isn't...
BTW, I like Paint.net...can't wait until I know a little more about c# and start tinkering with it.