Hi,
as posted in another thread, the examples/explain tabs worked for me after enabling the events_statements_current and events_statements_history consumers.
max_digest_length configures the max length for the normalized version (as shown in the screenshot)
max_sql_text_length configures the max length for the SQL_TEXT column, it is used as example (which is then used for the explain)
https://forums.percona.com/discussion/comment/57538/#Comment_57538