// TODO: translate the following.
// 'form.group_edit.display_options' => 'Display options',
// 'form.group_edit.show_holidays' => 'Show holidays',
+// 'form.group_edit.holidays' => 'Holidays',
// 'form.group_edit.tracking_mode' => 'Tracking mode',
// 'form.group_edit.mode_time' => 'time',
// 'form.group_edit.mode_projects' => 'projects',