message: Use Object.assign to set initial state of MessageComposerStore
  Otherwise we just modify the initial state when running
diff: @@ -32,7 +32,7 @@ class MessageComposerStore extends Store {
  super(dis);
  // Initialise state
  - this._state = INITIAL_STATE;
  + this._state = Object.assign({}, INITIAL_STATE);
  }
  _setState(newState) {
  