Add visual indication for "draft" messages

[artcodespace]

When using the current composer, if you:

• start writing a message in the composer in room "A"
• switch to a different room, room "B", and send some messages
• return to room "A"

Then you see in the composer the message that you started writing before you left room "A". This is very useful. Do you think that the usability of this would be improved if there was a visual indicator in the room list to show a user that they have a "draft" in that composer?

(I'm using the word draft for lack of a better word - using it here as shorthand for persisted message composer information).

I personally think this would be useful for situations where:

• A user is in one conversation, gets interrupted by another conversation (that takes a while) and so forgets what it was that they were responding to previously. The user could then look for the little draft indicator on the conversation as something to jog their memory and go back to what they were replying to before.
• A user writes a message, doesn't send it and completely forgets about it. On returning to the conversation quite a bit later, when the user goes to start a new message, the composer loads the old message they'd forgotten about. In this situation, the user may be surprised to see the old message that they'd written and not sent. Having a visual indicator that there is some sort of draft present would reduce this surprise on returning to the composer later, or perhaps help the user to notice that they'd written something and not sent it.