Others have reported a small gesture between the Pope and Melania, it seems he gave her a small package, perhaps a rosary - and she turned back to have it blessed.
also there was this...
“What do you give him to eat, potizza?” Francis asked, referring to the president and a Slovenian dessert.

The first lady, who was born in Slovenia, smiled and repeated “potizza.”  an inside joke between Melania and Pope Francis. And a reference to Trump's corpulent middle which he hides behind the too long tie and the open jacket.  This Pope doesn't miss a moment. 

Trump has been out flanked... insert smiley face.

Peace and all good