Hi Allen,
First of all, thank you for 4coder. While having used it for just a bit, it does feel nice to use.
If I may, I would suggest to have a platform keybinding buffer, the same as the scratch or message buffer, there at all time. I think it will help people get use to the binding if they don't feel like making a custom one yet, and this would eliminate the need to switch between the web doc and the editor.
This is a small usability gain that might pay off big in the long run for adoption.