Hi Igor, i have a question regarding the design of NBOpenGL. Why does the following offscreen method, deals with windows? NBOffscreenDisplay >>createOpenGLContext ctx := NBHostWindowContext createSpecificForPlatform. ctx createWindow: extent. ctx createContext: ctx defaultPixelFormat. I'm trying to include in the framework, support for MacOSX, starting with offscreen drawables support using CGL, therefore i would like to modify it to: NBOffscreenDisplay >>createOpenGLContext ctx := NBDisplayContext createSpecificForPlatform. ctx createContext: ctx defaultPixelFormat. NBGLDisplay NBDisplayContext NBOffscreenDisplay NBWindowedDisplay NBWinContext NBUnixContext NBMacOSXContext What do you think? Fernando