After getting the message, there is a notification in tray, with an option to answer without opening main chat window. If I send anything from using this field, and then open chat window, messages look like:

Me:
Me:
Me:
Me:
Another contact:
Another contact:
... and so on.

It doesn't mean I sent 4 messages one by one - in my case they should look like:

Me:
Answer from another contact:
My answer:
and so on.

Sorry for my Engilsh.