message: make sure the update callback gets a caret when calling reset
diff: @@ -149,6 +149,9 @@ export default class EditorModel {
  reset(serializedParts, caret, inputType) {
  this._parts = serializedParts.map(p => this._partCreator.deserializePart(p));
  + if (!caret) {
  + caret = this.getPositionAtEnd();
  + }
  // close auto complete if open
  // this would happen when clearing the composer after sending
  // a message with the autocomplete still open
  