Hazarat Maulana ASFRAF ALI THANWI arose and said that Alhamdullilah ALLAH (S.W.A.) had answered this question by putting the following answer in my heart. The Hadis is that there sould be no structure on the Grave. But in this case Hujra of Haz. AYESHA was in existence much much before the grave of Huzoor (S.A.W.) came into exixtence. Hence in the instant case the GUMBAD -E- KHIZRA is considered to be built on the Hujra of Haz. AYESHA (R.A.) and hence doesnot contradic the hadis.