adding scroll behaviour to presentation mode

src/app/modules/presentation/monitor/monitor.component.html

@@ -1,4 +1,5 @@
-<div [style.font-size.px]="zoom" class="fullscreen">
-  <app-song-text [showSwitch]="false" [text]="song.text" chordMode="hide"></app-song-text>
+<div *ngIf="song" [style.font-size.px]="zoom" class="fullscreen">
+  <app-song-text [fullscreen]="true" [index]="index" [showSwitch]="false" [text]="song.text"
+                 chordMode="hide"></app-song-text>
   <app-legal [song]="song"></app-legal>
 </div>

src/app/modules/presentation/monitor/monitor.component.less

@@ -1,3 +1,7 @@
+:host {
+  margin-top: 0 !important;
+}
+
 .fullscreen {
   position: fixed;
   top: 0;

src/app/modules/presentation/monitor/monitor.component.ts

@@ -14,7 +14,7 @@ import {Song} from '../../songs/services/song';
 export class MonitorComponent implements OnInit {
   public song: Song;
   public zoom: number;
-  private index: number;
+  public index: number;
   private sections: Section[];
 
   constructor(