frontend/src/app/tasks/task-detail-overview/task-detail-overview.component.html

@@ -16,7 +16,7 @@
       <p>ETA: {{task!.eta}} Minuten - Deadline: {{task!.deadline}}</p>
       <mat-progress-bar [mode]="'determinate'" [value]="task!.workTime"></mat-progress-bar>
     </mat-card-content>
-    <mat-card-actions>
+    <mat-card-actions *ngIf="taskgroup != undefined && task != undefined">
       <div style="width: 100%">
         <div style="float: left">
           <button mat-flat-button class="borderless-btn" color="primary" [routerLink]="['/taskgroups', taskgroup!.taskgroupID, 'tasks', task!.taskID, 'schedule']">Schedule</button>