code: function getActiveKey(keyName) {
  
          // Get key array for given name
          var keys = osk.keys[keyName];
          if (!keys)
              return null;
  
          // Find last matching key
          for (var i = keys.length - 1; i >= 0; i--) {
  
              // Get candidate key
              var candidate = keys[i];
  
              // If all required modifiers are pressed, use that key
              if (modifiersPressed(candidate.requires))
                  return candidate;
  
          }
  
          // No valid key
          return null;
  
      }
docs: Returns the single matching Key object associated with the key of the
  given name, where that Key object's requirements (such as pressed
  modifiers) are all currently satisfied.
  
  @private
  @param {String} keyName
  The name of the key to retrieve.
  
  @returns {Guacamole.OnScreenKeyboard.Key}
  The Key object associated with the given name, where that object's
  requirements are all currently satisfied, or null if no such Key
  can be found.