openproject/public/templates/work_packages/modals/group_by.html

<div class="ng-modal-window">
  <div class="ng-modal-inner">
    <div class="modal-header"><i class="icon-close" ng-click="modal.closeMe()"></i></div>

    <h3>Group by</h3>

    <div>
      <input id="selected_columns_new"
             type="hidden"
             ui-select2-sortable="select2Options"
             simple-query="getGroupableColumnsData"
             ng-model="selectedGroupByData"></input>
    </div>
    <div>
      <button class="button_highlight" ng-click="updateGroupBy()">Apply</button>
      <button class="button" ng-click="modal.closeMe()">Cancel</button>
    </div>

  </div>
</div>