I have setup filebeat/elastic/kibana to monitor my logs. In Kibana's discover page, if I hover the mouse over default fields (message, @timestamp etc), it shows + and - buttons for enabling "filter for value" and "filter out value" searches.
This feature which is very handy, however, does not work for custom fields. Specifically, I added a field call level and I would like to show only error messages. Is there a way to activate this UI feature in Kibana to work with custom fields as well?