Do you have 'debug info' set to 'show' in settings? That's usually the culprit but it should be set to off by default
@Gordon started
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
Do you have 'debug info' set to 'show' in settings? That's usually the culprit but it should be set to off by default