Hi there, I just purchased Artboard after being quite taken with the app when using the trial. I've found several bugs that I will post here (or wherever is most useful to you guys) as my schedule allows, but obviously I still love the app because I bought it
I set the drawing background color to 0% opacity... I intend to export a PNG with a transparent background, but I have a feeling that this is not necessary.
Anyway, when the background is set to 0% opacity, any redrawing to the drawing leaves trails like so:

This happened first time loading the app after it installed (full version) from the App Store. This is version 1.4, and I'm using a Mac Pro with Lion 10.7.3
Cheers,
-Sal