code: function() {
          var me = this,
              value = me.textField.getValue();
              
          if (value === '') {
              return null;
          }
          if (!me.regExpMode) {
              value = value.replace(me.regExpProtect, function(m) {
                  return '\\' + m;
              });
          } else {
              try {
                  new RegExp(value);
              } catch (error) {
                  me.statusBar.setStatus({
                      text: error.message,
                      iconCls: 'x-status-error'
                  });
                  return null;
              }
              // this is stupid
              if (value === '^' || value === '$') {
                  return null;
              }
          }
  
          return value;
      }
docs: In normal mode it returns the value with protected regexp characters.
  In regular expression mode it returns the raw value except if the regexp is invalid.
  @return {String} The value to process or null if the textfield value is blank or invalid.
  @private