<mat-tab-group [selectedIndex]="selectedIndex" (selectedTabChange)="selectedIndex = $event.index">
<mat-tab label="Instruction"></mat-tab>
<mat-tab label="test">
<div fxLayout="column" fxLayoutGap="5px" style="color: black;">
<mat-label>Description of Problem</mat-label>
<editor id="desOfProb"
formControlName="desOfProb"
[apiKey]="appSettings['tineMCE']['apiKey']"
[init]="appSettings['tineMCE']['init']">
</editor>
</div>
</mat-tab>
</mat-tab-group>
please see images and let me know if you have anything which I can try.