Hey guys, I felt the need to dive into an old Apple sample to understand how to do some advance window manipulation: http://developer.apple.com/samplecode/RoundTransparentWindow/index.html Porting the sample to MacRuby was pretty straight forward :) http://github.com/mattetti/macruby-roundtransparentwindow/tree/master Laurent, feel free to change the license and provide the example with MacRuby if you think that could help other developers. - Matt