Как управлять высотой полей в MODx.FormPanel?

Tests.panel.AddTest = function (config) {
  config = config || {};
  if (!config.id) {
    config.id = 'tests-add-items';
  }
  Ext.applyIf(config, {
    items: [
      {
        id: config.id + '-form',
        xtype: 'modx-formpanel',
        layout: 'form',
        url: Tests.config.connector_url,
        baseParams: {
          action: 'mgr/test/create'
        },
        items: [
          {
            xtype: 'textfield',
            fieldLabel: _('tests_item_name'),
            name: 'name',
            id: config.id + '-name',
            anchor: '99%',
            allowBlank: false
          },
          {
            xtype: 'textarea',
            fieldLabel: _('tests_item_description'),
            name: 'description',
            id: config.id + '-description',
            height: 150,
            anchor: '99%'
          },
          {
            xtype: 'textarea',
            fieldLabel: _('tests_item_instructions'),
            name: 'instructions',
            id: config.id + '-instructions',
            height: 150,
            anchor: '99%'
          },    
          {
            xtype: 'xcheckbox',
            boxLabel: _('tests_item_active'),
            name: 'active',
            id: config.id + '-active',
            checked: true
          }
        ],
        buttons: [
          {
            text: _('tests_item_submit'),
            cls: 'primary-button',
            scope: this,
            handler: function() {
              var form = this.get(config.id + '-form');
              form.submit({
                success: function(form, action) {
                  this.fireEvent('success', {
                    f: frm,
                    a: a
                  });
                },
                failure: function(form, action) {
                  this.fireEvent('failure', {
                    f: frm,
                    a: a
                  });               
                }
              });
            }
          }
        ]
      }
    ],
  });

  Tests.panel.AddTest.superclass.constructor.call(this, config);
};

Ext.extend(Tests.panel.AddTest, MODx.Panel);
Ext.reg('tests-add-items', Tests.panel.AddTest);