Tab keeps previous tab after push

Ionic Framework ionic-v3
1

Hi community.
I have two pages A and B.
In Page A, after a form validation, I redirect to page B with push.

                        this.app.getRootNav().getActiveChildNav().select(2);
                        scheduleCtrl.push(ContactPage);

When I click on tab A, I still have the page B. And when I click once in the tab A, at that time ionic show me page A.

How could I correct it please?
Please