<mat-form-field class="data-entry">
  <mat-label>Tutorial</mat-label>
  <mat-select multiple [compareWith]="compareSelection" [value]="student.tutorial_enrolments">
    <mat-optgroup *ngIf="tutorialsForStreamAndStudent(student).length > 0" label="No stream">
      <mat-option *ngFor="let tutorial of tutorialsForStreamAndStudent(student)" [value]="tutorial"
        (click)="switchToTutorial(tutorial)">
        {{tutorial.abbreviation}}
      </mat-option>
    </mat-optgroup>
    <div *ngFor="let stream of unit.tutorial_streams">
      <mat-optgroup *ngIf="tutorialsForStreamAndStudent(student, stream).length > 0" [label]="stream.name">
        <mat-option *ngFor="let tutorial of tutorialsForStreamAndStudent(student, stream)" [value]="tutorial"
          (click)="student.switchToTutorial(tutorial)">
          {{tutorial.abbreviation}}
        </mat-option>
      </mat-optgroup>
    </div>
  </mat-select>
</mat-form-field>

<mat-form-field floatLabel="never" class="data-entry">
  <mat-label>Tutorial</mat-label>
  <mat-select multiple [compareWith]="compareSelection" [value]="student.tutorial_enrolments">
    <mat-optgroup *ngIf="tutorialsForStreamAndStudent(student).length > 0" label="No stream">
      <mat-option *ngFor="let tutorial of tutorialsForStreamAndStudent(student)" [value]="tutorial"
        (click)="switchToTutorial(tutorial)">
        {{tutorial.abbreviation}}
      </mat-option>
    </mat-optgroup>
    <div *ngFor="let stream of unit.tutorial_streams">
      <mat-optgroup *ngIf="tutorialsForStreamAndStudent(student, stream).length > 0" [label]="stream.name">
        <mat-option *ngFor="let tutorial of tutorialsForStreamAndStudent(student, stream)" [value]="tutorial"
          (click)="student.switchToTutorial(tutorial)">
          {{tutorial.abbreviation}}
        </mat-option>
      </mat-optgroup>
    </div>
  </mat-select>
</mat-form-field>

Remove float label from label input
LOOKS: Remove float label from label input
