I was browsing through the documentation and reading some topics.

Caveats. Since users can edit events outside this mini window, or even just close that window without running our script.....

The mini windows are called by the script step "New Window".
What if I un-check in Window Styles / Specify Advanced Style the Window Controls, like Close...

Will that "force" the user to "use" the buttons on the window, and consequently be forced to use the script(s) ?