How to prevent Google Chrome "native" notifications from disappearing?

I've enabled Chrome native notifications:

chrome://flags/#enable-native-notifications

When I get an web notification, it shows for a second on the top side and also in Ubuntu's notifications area (click on the clock or super+v).

The problem is that it disappears even though I didn't "handle" it. I didn't click on it.

This causes me to lose track of pending stuff, like messages from co-workers.

Any idea how to keep the web notifications from disappearing?

Know someone who can answer? Share a link to this question via email, Twitter, or Facebook.