Hello there!
After extensive research combined with your feedback, we found that our Chrome app was causing some problems between your board and the Serial monitor.
Until now, if the data that the Serial monitor received from your board was more than 10 messages per second, the connection with the Serial monitor was lost and you received an error message displaying that codebender couldn't administer with such a fast data transfer rate.
Also, if you tried to repeatedly press the "Connect-Disconnect" button (on the Serial monitor), this led to a failed connection between your board and the Serial monitor.
Not only have we resolved these issues but we now provide you with a faster, lighter for your computer and more a stable Chrome app.
Our new app communicates better with the Arduino devices, and performs better on slower hardware. Our updated Chrome app will also increase the success rate of your projects' flashes and lower your battery consumption (when you are on a laptop).
For our advanced users, we have also created a better procedure for resetting the Arduino Uno boards.
You can drop us a line if you have any feedback, comments, or ideas!
Best,
codebender