Program: 69552
Project: 69552
Buggy source:
@Override protected void event(UserRequest ureq,Controller source,Event event){
  subm.setEnabled(true);
  if (source == groupChooseCoaches) {
    if (event == Event.DONE_EVENT) {
      cmc.deactivate();
      easyGroupCoachSelectionList.setValue(StringHelper.formatAsSortUniqCSVString(groupChooseCoaches.getSelectedNames()));
      easyGroupCoachSelectionList.setUserObject(groupChooseCoaches.getSelectedKeys());
      easyGroupCoachSelectionList.getRootForm().submit(ureq);
    }
 else     if (Event.CANCELLED_EVENT == event) {
      cmc.deactivate();
    }
  }
 else   if (source == areaChooseCoaches) {
    if (event == Event.DONE_EVENT) {
      cmc.deactivate();
      easyAreaCoachSelectionList.setValue(StringHelper.formatAsSortUniqCSVString(areaChooseCoaches.getSelectedNames()));
      easyAreaCoachSelectionList.setUserObject(areaChooseCoaches.getSelectedKeys());
      easyAreaCoachSelectionList.getRootForm().submit(ureq);
    }
 else     if (event == Event.CANCELLED_EVENT) {
      cmc.deactivate();
    }
  }
 else   if (source == groupChooseParticipants) {
    if (event == Event.DONE_EVENT) {
      cmc.deactivate();
      easyGroupParticipantsSelectionList.setValue(StringHelper.formatAsSortUniqCSVString(groupChooseParticipants.getSelectedNames()));
      easyGroupParticipantsSelectionList.setUserObject(groupChooseParticipants.getSelectedKeys());
      easyGroupParticipantsSelectionList.getRootForm().submit(ureq);
    }
 else     if (Event.CANCELLED_EVENT == event) {
      cmc.deactivate();
    }
  }
 else   if (source == areaChooseParticipants) {
    if (event == Event.DONE_EVENT) {
      cmc.deactivate();
      easyAreaParticipantsSelectionList.setValue(StringHelper.formatAsSortUniqCSVString(areaChooseParticipants.getSelectedNames()));
      easyAreaParticipantsSelectionList.setUserObject(areaChooseParticipants.getSelectedKeys());
      easyAreaParticipantsSelectionList.getRootForm().submit(ureq);
    }
 else     if (event == Event.CANCELLED_EVENT) {
      cmc.deactivate();
    }
  }
}

Fixed version (ground truth):
@Override protected void event(UserRequest ureq,Controller source,Event event){
  subm.setEnabled(true);
  if (source == groupChooseCoaches) {
    if (event == Event.DONE_EVENT) {
      cmc.deactivate();
      easyGroupCoachSelectionList.setValue(getGroupNames(groupChooseCoaches.getSelectedKeys()));
      easyGroupCoachSelectionList.setUserObject(groupChooseCoaches.getSelectedKeys());
      easyGroupCoachSelectionList.getRootForm().submit(ureq);
    }
 else     if (Event.CANCELLED_EVENT == event) {
      cmc.deactivate();
    }
  }
 else   if (source == areaChooseCoaches) {
    if (event == Event.DONE_EVENT) {
      cmc.deactivate();
      easyAreaCoachSelectionList.setValue(getAreaNames(areaChooseCoaches.getSelectedKeys()));
      easyAreaCoachSelectionList.setUserObject(areaChooseCoaches.getSelectedKeys());
      easyAreaCoachSelectionList.getRootForm().submit(ureq);
    }
 else     if (event == Event.CANCELLED_EVENT) {
      cmc.deactivate();
    }
  }
 else   if (source == groupChooseParticipants) {
    if (event == Event.DONE_EVENT) {
      cmc.deactivate();
      easyGroupParticipantsSelectionList.setValue(getGroupNames(groupChooseParticipants.getSelectedKeys()));
      easyGroupParticipantsSelectionList.setUserObject(groupChooseParticipants.getSelectedKeys());
      easyGroupParticipantsSelectionList.getRootForm().submit(ureq);
    }
 else     if (Event.CANCELLED_EVENT == event) {
      cmc.deactivate();
    }
  }
 else   if (source == areaChooseParticipants) {
    if (event == Event.DONE_EVENT) {
      cmc.deactivate();
      easyAreaParticipantsSelectionList.setValue(getAreaNames(areaChooseParticipants.getSelectedKeys()));
      easyAreaParticipantsSelectionList.setUserObject(areaChooseParticipants.getSelectedKeys());
      easyAreaParticipantsSelectionList.getRootForm().submit(ureq);
    }
 else     if (event == Event.CANCELLED_EVENT) {
      cmc.deactivate();
    }
  }
}