Some days ago I activated this new editor in https://de.wikipedia.org/wiki/Spezial:Einstellungen#mw-prefsection-betafeatures . As I saw some features are missing (e.g. „Simple mode“ - hide refs etc.) or difficult to reach (preview, changes – already mentioned here), I turned back and deactived this new editor.
The old editor appeared, but if I activated the right toolbar button „Simple mode“, all in the edit area appeared in plain text without syntax highlighting, only the right toolbar was visible, and if I deactivated the toolbar button „Simple mode“, nothing happened.