in sample/frontend/src/app/shared/fix/drag-column.directive.ts [59:68]
private unbindEvents() {
if (this.dragStartListener) {
this.elementRef.nativeElement.removeEventListener('dragstart', this.dragStartListener);
this.dragStartListener = null;
}
if (this.dropListener) {
this.elementRef.nativeElement.removeEventListener('drop', this.dropListener);
this.dropListener = null;
}
}