Thanks for removing .git folder. Since the end user don't know the entry value is going directly to the terminal command, you need to make sure `entry.get_text()` is always a valid integer before spawning the command line. To do that I recommend to use parseInt(): https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseInt Also check whether the parseInt() result isn't NaN. Please join us on GNOME Matrix channel if you have any questions related to the extensions: https://matrix.to/#/#extensions:gnome.org