- UNG main listbox was renamed from 'your_listbox' to 'listbox'

- Reuse mixin methods

- Does not need to wait
- Break lines to not extend so much

- When many events are present on same day, a button ("Other##") is created,
  in order to show other events and not break main calendar layout

- Also call wait_for_activities when asked for

- Call wait_ung_calendar_to_load when opening 'calendar' page
- Call wait_ung_listbox_to_load when opening 'ung' page

Because now this dialog is only rendered when user clicks to load it