QAN explain can't show

Hi , I have installed pmm 1.0.7 ,includes client and server.
But I can’t see the explain in QAN. Why? Thanks.

I can see ‘explain’ information in

EXPLAIN is available only when there are any query examples for the chosen fingerprint query. They can be turned off (by default, it’s ON). Also if using performance_schema as a query source, query examples are not always available depending from the load etc. You can check other queries, they may have query examples, thus EXPLAIN.

Other queries ,I still can’t see any query examples . Which parameters are related to query examples ? Or How do I turn off ?

Settings page for chosen server (gear icon).