Currently, the SMS app requests 10 message when a conversation is opened. If that is not enough to fill the screen, the view looks strange and is difficult to scroll because the scroll bar does not show. The model should request enough messages to fill the view rather than a hard-coded number.
One way to do this is to literally request a single message, wait for the Dbus interface to reply (should be very quick in all cases), then see if the view is full. If not, request another message and repeat.
The solution to this will likely be relevant to solving T10186