codelab: control focus with FocusTrap

Author: twerske

src/app/shop/color-picker/color-picker-dialog/color-picker-dialog.component.html

@@ -15,7 +15,7 @@
 -->
 <div mat-dialog-content>
   <!-- TODO: #10. Control focus with FocusTrap -->
-  <mat-selection-list #colors aria-label="Dumpling wrapper color" multiple="false">
+  <mat-selection-list #colors aria-label="Dumpling wrapper color" multiple="false" cdkFocusInitial>
     <mat-list-option *ngFor="let paint of defaultColors" [value]="paint" color="primary">
       <div class="color-option">
         <div class="circle" [ngStyle]="{'background': paint}"></div>