As of today, the web-based design tool we'll be using in the workshop is compatible with all 4 major browsers when used without Internet access. It's always worked with all 4 when accessed on the web, but until now if you wanted to access a copy on your hard drive without a web server, you were limited to only Firefox.
Now Safari, Chrome, IE and Firefox all work without access to any server. Linux, Macintosh and Windows are fully supported.
There were basically 2 issues. First was removing some leftover code from Node-Red (an open source IoT project where most of the GUI code came from) which loaded extra stuff from the server at startup. There's really no need, so all the documentation html was merged into the main file and that loading step disabled. The second part involved removing still more leftover cruft which interfered with Google Chrome when accessing without a server. Thanks to HWGuy on the forum for pointing out the issues impacting Chrome!
The HTML file is buried pretty deep inside Arduino's folder structure, so accessing the web server is still simpler. But if we don't have internet access, you can dig down several folders and open the right index.html file, and it will "just work" regardless of whether you use Chrome, Firefox, IE or Sarafi.