Ionic 4 Popover arrow

I would like to insert a popover like the Ionic official example but I can’t see the arrow (popover-arrow).
What should I do?
In the example it is displayed but even going to see the source code I cannot understand how it can appear.

Hello, maybe try add
detail=true in ion-item tag

Ionic official documentation - Item detail rows

I test it on iOS simulator and it works.
When i pos the problem i was seeing the popover on the browser.