Why am I seeing "No filters available"?
You'll usually see the "No filters available" message if your Event field is still set to All Events.
If you change this to a specific event, you'll then see additional options if they are available for your account and you'll be able to use the Filter by field as expected.
How do I add more filters?
Currently, the Filter by field allows one selection for event filters.
If you need additional filtering, we suggest creating a Custom Event in your Mixpanel account, including any filters needed there. Then you can display the Custom Event in Geckoboard.