Janaazah

Dua after Janaazah Salaah

Q:

1. We notice that in some places the Imaam makes dua immediately after the janaazah salaah. Is this correct and among the Sunnah practices of janaazah Salaah?

2. If dua after the janaazah Salaah is not correct, however, for the sake of keeping the peace, can it be done?