Ionic 4 Show Tab Conditionally

I have always found that using *ngIf with tabs to be challenging in any version of Ionic, but I am having little success in v4 now. While I can use something simple to set the initial state of the tab. Later showing the tab after the fact proves to be difficult.

 <ion-tab label="Some Label" icon="contacts" href="/tabs/(contact:contact)" *ngIf="showTab">
    <ion-router-outlet name="some-outlet"></ion-router-outlet>

If I set showTab to false in the beginning, it hides successfully. Later when I change showTab to true, the tab is not shown. What is the proper way to change visibility of a tab in Ionic 4 after it has been rendered?