anchor.diff:          optionalInputBox =
             <input type='text' value={this.state.grace_credits_input} onChange={this.graceCreditsChanged} />
         } else if (this.state.select_value == 'update_section') {
  -        if (this.props.sections) {
  +        if (this.props.sections.length > 0) {
             var section_options = [];
             for (var i = 0; i < this.props.sections.length; i++) {
               var section = this.props.sections[i];
  
positive.code:           section_id: ''
          });
        } else if (event.target.value == 'update_section') {
          if (this.props.sections) {
            var initial_section = this.props.sections[0].id;
            this.setState({
              grace_credits_input: '0',
  
negative.code:               <option value='give_grace_credits'><%= j raw I18n.t(:'give_grace_credits') %></option>
                <option value='update_section'><%= j raw I18n.t(:'add_section') %></option>
                <option value='hide'><%= j raw I18n.t(:'hide_students') %></option>
                <option value='unhide'><%= j raw I18n.t(:'unhide_students') %></option>
              </select>
              {optionalInputBox}
              {applyButton}
  