Fixed missed function call after extracting out some code into a separate method

src/app/plan-display/plan-display.component.ts

@@ -61,6 +61,8 @@ export class PlanDisplayComponent implements AfterViewInit, OnInit {
       this.currentPlan = plan;
       setTimeout(() => this.setIndex(plan.current), 0);
     })
+
+    this.registerOnZoneEnter();
   }
 
   registerOnZoneEnter() {