Is it permissible to leave the Musjid after the Imaam's Salaam?

Answer

It is permissible to leave the Musjid after the Imaam has terminated the Jamaat Salaat with Salaam. The Sunnats may be performed at home. However, one should not unnecessarily abandon the Dua after the Fardh Salaat. After Zuhr, Isha and Maghrib, make a short silent dua. There is no need to wait until the Imaam ends his long dua. After Fajr and Asr Fardh, the Dua is usually longer. It depends on the individual. Again it is not necessary to remain as long as the Imaam makes dua.

After the short dua one may leave to avoid becoming involved in conversation outside the Musjid. It is permissible, in fact necessary, to engage in the Sunnat Salaat whilst the Imaam is involved with his long bid'ah dua.