code: function release(keyName, keyElement) {
  
          // Release key if currently pressed
          if (pressed[keyName]) {
  
              removeClass(keyElement, "guac-keyboard-pressed");
  
              // Get current key based on modifier state
              var key = getActiveKey(keyName);
  
              // Send key event if not a modifier key
              if (!key.modifier && osk.onkeyup)
                  osk.onkeyup(key.keysym);
  
              // Mark key as released
              pressed[keyName] = false;
  
          }
  
      }
docs: Releases the key having the given name, removing the
  "guac-keyboard-pressed" CSS class from the associated element. If the
  key is already released, this function has no effect.
  
  @private
  @param {String} keyName
  The name of the key to release.
  
  @param {String} keyElement
  The element associated with the given key.