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Leaving 'use beta quest' unchecked will ensure you remain on the stable code base that may not offer the enhanced functionality, but does function for what it offers to without error. If you do want to get back on beta, please replace 'quest' in the URL with 'lbtest' to have the option to again go to your account and select use beta quest (and then try https://quest.cns.utexas.edu/instructor/courses ).
If you're back on the stable code base (with more white space) and want to move over to the other side, you can launch from :
https://lbtest.cns.utexas.edu/instructor/courses
Which will provide you both the new layout and the option to go to the new code base as your default by following the steps above.
Feedback always welcome! Please feel free to let us know your thoughts at questhelp@austin.utexas.edu.
Survey specific to the new code base accessible here.