I am not able to select different ringtones for two sim due to this. This dialer has many probles with MI phones. 1) If I take away phone from ear, screen do not wake up. 2) If I connect phone with earphones, it don't sleep. 3) If I remove single permission, video call hangs entire screen. By any chance camera starts, you can not just turn back to audio call. Phone baught two months ago and there is no default dialer. Need to use this. These issues exist in all new MI phones.