code: function() {
              if (!this.clearOnEscape) {
                  return;
              }
  
              // Using a KeyMap did not work: ESC is swallowed by combo box and date field before it reaches our own KeyMap
              this.textField.inputEl.on('keydown',
                  function(e) {
                      if (e.getKey() == Ext.EventObject.ESC) {
                          if (this.textField.isExpanded) {
                              // Let combo box or date field first remove the popup
                              return;
                          }
                          // No idea why the defer is necessary, but otherwise the call to setValue('') is ignored
  
  						// 2011-11-30 Ing. Leonardo D'Onofrio leonardo_donofrio at hotmail.com
  						if (this.textField.clearValue) {
  							Ext.Function.defer(this.textField.clearValue, 1, this.textField);
  						} else {
  							Ext.Function.defer(this.textField.setValue, 1, this.textField, ['']);
  						}
                          // end Ing. Leonardo D'Onofrio
  						e.stopEvent();
                      }
                  },
                  this);
          }
docs: If config option "clearOnEscape" is true, then add a key listener that will clear this field