When editing the last message, displayed message is not updated (v5)

[graven]

To reproduce:

1. Write something in chat
2. Press up arrow
3. Change the text of the last message

Expected:
Text changed to whatever is written at step 3

Actual:
Rendered text does not change (shows whatever was written at step 2)

Additional info:
If step 2 is repeated, Skype proposes to edit the message entered at step 3. The conversation parties also see the text that is entered at step 3.