Editing message too quickly is breaking chat view

[l0ud]

To reproduce:

• Send message to chat
• Press arrow up key quickly (I do that very often after realizing some mistake)

Now:

• you cannot edit that message, you can press enter but nothing happens
• you cannot post new message either.
• you can see "Possibly unhandled rejection: undefined" in javascript console each time you press enter.

To unlock posting you need to either refresh browser window, or switch to another chat and go back again.