Usage tips:
1. Click on a bulleted event group name to unfold the list of event types (another click will fold it back). Event types for which there are not enough occurrence locations (option above) will either be hatched or completely hidden (also option above).
2. Click on any event type. A list of selected event types will appear below the menu, as well as a search button for places.
3. Repeat steps 1 and 2 until you have created a list of event types you want to investigate. Each event in the list has an 'x' button for removal from the list.
4. Click the search button and after a while you will see a table with the locations of the selected events. You can sort the table freely, search for places in it, change the paging.