Looks amazing! I'm working on a diagram editor (UML and business processes) for Google Wave where we had to solve command ordering/merging and a lot of similar

Looks amazing! I'm working on a diagram editor (UML and business processes) for Google Wave where we had to solve command ordering/merging and a lot of similar problems. We developed a javascript library to synchronize a command stack between clients and resolve all ordering problems that could occur due to commands arriving very late. Having a server like you do for synchronization and that stuff would make those issues nearly trivial to solve- but as Google Wave only provides a synchronized key-value storage we had to roll our solution client side only. You might want to check out our approach in a little more depth at http://www.processwave.org/2010/02/syncro-real-collaboration-in-google.html http://www.processwave.org/2010/02/syncro-real-collaboration... or take a look at the very well documented code at the bitbucket: http://bitbucket.org/processwave/syncro http://bitbucket.org/processwave/syncro We are planning on adding a paint canvas to our app, and yours looked the best I saw so far in a webapp. Cool work, it's not trivial stuff :)