code: public function setFrameFocus($name)
      {
          if (is_integer($this->focus)) {
              if ($this->frames[$this->focus]->hasFrames()) {
                  return $this->frames[$this->focus]->setFrameFocus($name);
              }
          }
          if (in_array($name, array_keys($this->names))) {
              $this->focus = $this->names[$name];
  
              return true;
          }
  
          return false;
      }
docs: Sets the focus by name.
  If already focused and the target frame also has frames,
  then the nested frame will be focused.
  
  @param string $name    Chosen frame.
  
  @return bool        True if frame exists.