It is not only on the frontend, also on the menu allocation page, where i want a single event to be displayed, the dropdown box is empty !
I have looked at the database tables and there are som problems there.
The table holding the events has a field containing the value of the group. But there is also a table contaning event and group. It seems as if they wanted it to be possible to assign an event to multiple groups, but somehow it is now messed up. Some pages use the old group and some the new. Clearly a bug !!