TFJS Debugger - Feature Request: warning upon closing editor

[jenperson]

When using the code editor for generating tensors or post-processing, the buttons are labeled Execute and Done. It can be easy to exit the code editor before running the code, and the developer may not realize that it hasn't run. I suggest one of the three following solutions:

1. Remove the Done button and instead put an X in the top corner of the pop-up.
2. Change Done to Close. This might not fully fix the issue, but it could help.
3. Add a warning pop-up when clicking Done to confirm that the user meant to close. This pop-up could include a Run button so users can run the code without having to return to the editor.