As reported on the German-language Wikipedia's feedback page, the VisualEditor stalls when trying to add a link to wikitext with the HTML entity.
Steps to reproduce:
- Open a new page in source mode (preferably on dewiki) and add VO (EWG) Nr. 1408/71
- Switch to visual editing, mark the text and create a link to the page Verordnung (EWG) Nr. 1408/71
- Observe that one can neither click "Fertig" (done) or "Abbrechen" (cancel)
(During testing I noticed that switching to source mode and back again seems to help. Afterwards, it is possible to change the link target without any problems.)