Person A is online and sends a message to person B; person B is offline but opens the message, is "seen" still displayed to person A?

Question

Person A sends a message via chat or just normal private messaging on to person B..

Person B opens the message in there private message area, but is offline on facebook chat..

Questions

1. Does person A still receive the "seen" notification that there message has been seen?

2. If person B just clicks the envelope icon on the top bar at facebook to preview the message but doesn't open it is the "seen" notification still displayed to person A?

Answer 1

Opening the "Preview" (Chat icon in the top bar) does not trigger the read receipt, neither does going to facebook.com/messages/. But opening the conversation (facebook.com/messages/?action=read&tid=id.123456789) by clicking on the message or opening the chat window sets the "seen" flag and Person A will see it although B is offline.

Source: Just tested