openproject/frontend/app/components/wp-table/timeline/controls/wp-timeline.dummy-controls.directive.html

<div class="wp-timeline--dummy-controls hide-when-print" ng-if="$ctrl.wpTimeline.visible">
  <div class="timeline-controls--zoom-buttons">
    <button class="button -transparent"
            ng-disabled="$ctrl.currentZoom == $ctrl.maxZoomLevel"
            ng-click="$ctrl.updateZoom(1)">
      <i class="button--icon icon-zoom-out"></i>
    </button>
    <button class="button -transparent"
            ng-disabled="$ctrl.currentZoom == $ctrl.minZoomLevel"
            ng-click="$ctrl.updateZoom(-1)">
      <i class="button--icon icon-zoom-in"></i>
    </button>
   </div>
</div