code: protected void removeErrorMessage(String message)
  	{
  		fErrorMessages.remove(message);
  		if (fErrorMessages.isEmpty())
  		{
  			addErrorMessage(null);
  		} else
  		{
  			addErrorMessage((String) fErrorMessages.get(fErrorMessages.size() - 1));
  		}
  	}
docs: Removes the given error message from the errors currently displayed on this page. When an error message is
  removed, the page displays the error that was added before the given message. This is akin to popping the message
  from a stack. Clients should call this method instead of setErrorMessage(null).
  
  @param message
  the error message to clear