tweak options for footer observer

explore/src/app/app.component.ts

@@ -135,6 +135,11 @@ export class AppComponent {
 	}
 
 	createObservers() {
+		let options = {
+			root: null,
+			rootMargin: '0px',
+			threshold: 0.1
+		};
 		let intersectionObserver = new IntersectionObserver(entries => {
 			entries.forEach(entry => {
         if (entry.isIntersecting && this.showQuickContact) {
@@ -145,7 +150,7 @@ export class AppComponent {
           this.quickContactService.setDisplay(this.showQuickContact);
         }
       });
-		});
+		}, options);
 		intersectionObserver.observe(this.bottom.nativeElement);
 		this.subscriptions.push(intersectionObserver);
 	}