We just faced an issue of the Atelier main menubar being disabled (greyed out) after upgrading the macOS development machine to High Sierra. I would like to share my findings about the issue and how to fix it.
This seems to be a known problem affecting several Java applications including Eclipse if the macOS user's primary language is not English: https://www.eclipse.org/org/press-release/20170925criticalbug.php
I fixed the problem by applying the third workaround (not testing the first and second) listed in the referenced announcement as it seemed the least invasive one (just make sure to modify the Atelier.ini file instead of eclipse.ini in case of a stand-alone Atelier installation). Once Atelier/Eclipse is updated to the to-be-released Oxygen 4.7.1a version, the workarounds shouldn't be needed.