How to enable script editor of Docs, etc. in Google for Education accounts

Question

I made an error -- I tried to use the code in a Google Sheets file, not Google docs. It works in a new Google Doc file I created. This Request can be CLOSED. Thank you.

*****original request is below****** Although the exact text of a Google doc script works in a regular gmail account document, it fails in a Gmail for education acct, and I assume I need to change settings in the admin console (I am admin.) Does anyone know what the setting is that I need to change? And should I only change it for myself? IOW is it a poor choice for my students to be able to edit scripts in their documents?

This what works in one doc, but not another:

function onOpen() {
  DocumentApp.getUi().alert("Please check out the STEM Day Topics Tab, and Put your name on one you'd like to support!")
}

It creates a popup as expected in a non edu account. In the edu acct, I see a "working" message sometimes, but no popup.