Extension Schoology Plus' theme editor doesn't work

This one might be hard to debug (because you need to use a specific site to use the extension), but here goes:
Steps to reproduce:

1. Install the extension Schoology Plus
2. Go to Schoology and open the extension's theme editor
3. Attempt to choose any theme
4. See that nothing happens

Expected behavior:
Saving the theme works

Orion, OS version; hardware type:
Version 0.99.119-beta (WebKit 615.1.1)
MacBook Air (macOS Monterey 12.5.1 build 21G83)

I think this relates to how the theme editor depends on the chrome-extension: scheme working, because no address shows in the address bar when the editor opens.