We can find in the above narration that how much it was difficult for Umar bin Khattab to know the verse of KALALA. Umar bin Khattab asked about this from the Prophet(pbuh) again and again and annoyed the Prophet.
We are thinking about our Sunni fellows who believe that if there would be prophet after Prophet Mohamamd (pbuh) it would be Umar bin Khattab and Umar bin Khattab changed the rules of Quran and Sunnah as we have shared above and also in our research about Bukhari. Umar bin Khattab himself was not able to know the verse of KALALA easily!