good work, its nice app. I like the concept, after playing about with penpen though im thinking it might be an idea to create a seperate app if you intend on creating a flipbook style app. Just curious are you using pyqt for this? If so is opengl accelration being used for the graphicsview? i noticed as sketched it would get alittle laggy, if you where evolve this into a simple flipbook it could get more sluggish when you add features like onion skinning. Anyways nice app, i too vote for ctrl z. cheers nick